for some reason 2 consequtive yandex api calls produced such effect
replacing two calls with one reduces this a lot

It's that simple. Just wrong function was used)

Fix shramov#253, and part of shramov#111.

Note: zoom animation still fails
(shramov#129)

Fix shramov#287

…ded in `options`

---
@factory L.yandex(<String> type?, <Object> options)
Instantiates a Yandex layer object given `type` and `options` arguments (both optional).
Can be used with single `options` argument, if it contains `type` property.

@option type: String = 'yandex#map'
The same as `type` argument.

* enhance sample code
* upgrade to use latest leaflet
* upgrade to https

* L.Layer is already inherited from L.Evented
  As for L.Mixin.Events, then we do not support Leaflet 0.x

* actual max available zoom level is 19

* _insertAtBottom, _limitedUpdate: was not used

* getAttribution is already in L.Layer

* _reset contains _initContainer, which already called in onAdd
   And as we already have container, it makes no sense to check it on 'viewreset'

* setOpacity: no need to expose it

* setElementSize: is excessive, as css '100%' is to follow map resize.

* undefined is same as false in conditions

* consistent curly braces usage and other minor style issues

…aps initialized

* remove overlay option, it's now controlled by 'overlay' map type
  - opacity for overlay is handled automatically
    but (for compatibility reasons) `opacity` option is still able to override default value
  - background is now transparent for all map types, but this can be canceled by `background` option

* simplify map type handling
  Note: 'publicMap' and 'publicMapHybrid' are valid map types,
  but currently they are identical to 'map' and 'hybrid'

* JSAPI 2.0 is not supported anymore.
  It would need complex handling to keep it working with both api sets.

* Simplify `_initMapObject` as new api is able to auto-load required modules

* replace `traffic` option with `trafficControl`

* add `mapOptions` option: https://tech.yandex.com/maps/doc/jsapi/2.1/ref/reference/Map-docpage/#Map__param-options
  Refs:
    https://tech.yandex.ru/maps/jsapi/doc/2.1/ref/reference/Map-docpage/#Map__param-options.suppressMapOpenBlock
    https://tech.yandex.com/maps/jsapi/doc/2.1/ref/reference/Map-docpage/#Map__param-options.yandexMapDisablePoiInteractivity
    https://tech.yandex.com/maps/jsapi/doc/2.1/ref/reference/Balloon-docpage/#Balloon__param-options.autoPan
    auto pan should be disabled to prevent uncoordinated layers offset (or we may just disable poi interactivity to avoid balloon handling)

* add two new map types to cover all existing layer types (see ymaps.layer.storage)

---
@Class L.Yandex
@inherits L.Layer
Used to load and display tile layers on the map using Yandex JSAPI 2.1
https://tech.yandex.com/maps/doc/jsapi/2.1/quick-start/index-docpage/

@example

```js
L.yandex('yandex#satellite'}).addTo(map);
```

@section Map type
@example

Possible basemap types: `yandex#map`, `yandex#satellite`, `yandex#hybrid`, `yandex#map~vector`
or their short names: `map`, `satellite`, `hybrid`, `map~vector`

Possible overlay types:
`overlay` - empty transparent map, which can be used for displaying data provided e.g. by controls.
`skeleton` - roads and labels, like in `hybrid` (but w/o basemap).

@event MapObjectInitialized: Event
Fired after Yandex map object is initialized.
Event listener receives object containing `mapObject` property.

@option mapOptions: Object (see in sources)
Options to set on map creation:
https://tech.yandex.com/maps/doc/jsapi/2.1/ref/reference/Map-docpage/#Map__param-options

@option overlayOpacity: Number = 0.8
Opacity used for map type `overlay`.

@option opacity: Number = undefined
Force map opacity to given value.
Not really useful, but kept for compatibility.

It's bad practice, and may conflict with other leaflet controls, css, and actual developer intentions.
And it even do not work in some cases, e.g. when 2 yandex layers added, and then remove 1.

Besides, we do not need two attribution controls anyway (and it looks ugly).
It'd be better to gather all info in 1 (either Yandex's, either Leaflet's), and there is API for this.

Choosing appropriate decision is up on developer now.
If he want to change margins - let him do this explicitely.
And there are plenty of other options, among them:
- move attribution control to other corner
- disable attribution control completely
- implement dynamic attribution fetching from one control to another

Previously overlay was positioned over map pane, and this prevented normal
interaction with features (like markers, popups, etc).

Correct z-order can be provided only if overlay belongs to same stacking context
as the rest of panes, thats why we have to make it descendant of leaflet-map-pane.

But as map pane is panning on drag, it's now necessary to update ymaps offset in opposite order
to fit into visible window.

---
Note, that currently ymaps controls/copyrights belong to the rest of layer:
- positioned *behind* leaflet controls / features
- moving along with ground (tile) layer on drag
  (not an issue when updating is fast)

It's possible to fix it, if we divide ymaps panes into different containers.
That could lead to other issues thought..
So let it as is for now.

ymaps controls and copyrights shouldn't animate

Note: we need to ensure that 'leaflet-zoom-animated' class is set,
as more panes can be added in runtime

* prevent container removing in onRemove until api initialized.
  ymaps API currently expecting DOM element (to support IE).
  Other browsers also affected when load param mode=debug
  https://tech.yandex.com/maps/jsapi/doc/2.1/dg/concepts/load-docpage/#load__param

* prevent repeated map object initialization when layer removed/added before api is initialized
  onAdd / _initContainer refactored

For optimization purposes L.Yandex does not destroy itself onRemove (like simple tile layers do)
But it's still better to clean up on map unload

* _container.id is not set anymore
*  leaflet-map-pane class is not set anymore
* `MapObjectInitialized` is renamed to more typical `load` event
  `mapObject` property is removed, as it's available as `target._yandex`

---
@event load: Event
Fired after Yandex map object is initialized.

…d using ymaps JSAPI directly

usage sample provided in yandex.html
(it's also example of 'load' event usage)

…ntrol), via ymaps JSAPI

see yandex-controls.html

This addon allows using of Yandex controls just specify them in options,
without direct ymaps JSAPI calls.

see yandex-addon-controls.html (functionality is the same as in yandex-controls.html)

It's function is opposite to `_update`: resync center/zoom back from _yandex to map.

Intended to use in (upcoming) addons
(L.Yandex itself currently does not use it internally)

Purpose: to integrate panoramas player with leaflet map, avoiding controls conflicts.
It's function is to take player out of map and put it into separate element.

see yandex-addon-panorama.html

Purpose: enable standard Yandex map controls/behaviors in fullscreen.

see yandex-addon-fullscreen.html

…ialized

It's purpose is dynamic/deferred runtime API enabling.

Yandex.js: _initApi method for extending in addon

See examples/yandex-addon-loadapi-*.html

Another sample loader function similar to used in https://gitlab.com/IvanSanchez/Leaflet.GridLayer.GoogleMutant/:

```
 	function apiLoader() {
		return new Promise(function (resolve, reject) {
			var timer = setInterval(function () {
				if (typeof ymaps !== 'undefined') {
					resolve();
				} else if (counter<10) {
					counter++; return;
				} else {
					reject('API is not available');
				}
				clearInterval(timer);
			}, 500);
		});
	}
```