feat(*): change file naming convention

To align with the NPM package name `angular2-google-maps`
and the main module name, which uses dashes, we use dashes
insted of underscores in all source filenames.

BREAKING CHANGE:
When you import a directive directly, you have to change the
import path:

Old:
```
import {SebmGoogleMap} from 'angular2-google-maps/directives/google_map';
```

New:
```
import {SebmGoogleMap} from 'angular2-google-maps/directives/google-map';
```

Author: sebholstein

src/core.ts

@@ -1,7 +1,7 @@
 import {Provider} from 'angular2/core';
 
-import {MapsAPILoader} from './services/maps_api_loader/maps_api_loader';
-import {LazyMapsAPILoader} from './services/maps_api_loader/lazy_maps_api_loader';
+import {MapsAPILoader} from './services/maps-api-loader/maps-api-loader';
+import {LazyMapsAPILoader} from './services/maps-api-loader/lazy-maps-api-loader';
 
 // main module
 export * from './directives';

src/custom_typings/google_maps.d.ts renamed to src/custom-typings/google-maps.d.ts

@@ -0,0 +1,4 @@
+import {SebmGoogleMap} from './directives/google-map';
+import {SebmGoogleMapMarker} from './directives/google-map-marker';
+
+export const ANGULAR2_GOOGLE_MAPS_DIRECTIVES: any[] = [SebmGoogleMap, SebmGoogleMapMarker];

src/directives-const.ts

@@ -1,3 +1,3 @@
-export {SebmGoogleMap} from './directives/google_map';
-export {SebmGoogleMapMarker} from './directives/google_map_marker';
-export {ANGULAR2_GOOGLE_MAPS_DIRECTIVES} from './directives_const';
+export {SebmGoogleMap} from './directives/google-map';
+export {SebmGoogleMapMarker} from './directives/google-map-marker';
+export {ANGULAR2_GOOGLE_MAPS_DIRECTIVES} from './directives-const';

src/directives.ts

@@ -7,7 +7,7 @@ import {
   EventEmitter,
   Output
 } from 'angular2/core';
-import {MarkerManager} from '../services/marker_manager';
+import {MarkerManager} from '../services/marker-manager';
 
 let markerId = 0;
 

src/directives/google_map_marker.ts renamed to src/directives/google-map-marker.ts

@@ -1,6 +1,6 @@
 import {Component, Input, Renderer, ElementRef, NgZone} from 'angular2/core';
-import {GoogleMapsAPIWrapper} from '../services/google_maps_api_wrapper';
-import {MarkerManager} from '../services/marker_manager';
+import {GoogleMapsAPIWrapper} from '../services/google-maps-api-wrapper';
+import {MarkerManager} from '../services/marker-manager';
 
 /**
  * Todo: add docs

src/directives/google_map.ts renamed to src/directives/google-map.ts

@@ -1,7 +1,7 @@
-export {MapsAPILoader} from './services/maps_api_loader/maps_api_loader';
-export {NoOpMapsAPILoader} from './services/maps_api_loader/noop_maps_api_loader';
+export {MapsAPILoader} from './services/maps-api-loader/maps-api-loader';
+export {NoOpMapsAPILoader} from './services/maps-api-loader/noop-maps-api-loader';
 export {
   LazyMapsAPILoader,
   LazyMapsAPILoaderConfig,
   GoogleMapsScriptProtocol
-} from './services/maps_api_loader/lazy_maps_api_loader';
+} from './services/maps-api-loader/lazy-maps-api-loader';

src/directives_const.ts

@@ -2,7 +2,7 @@ import {Injectable} from 'angular2/core';
 import {Observer} from 'rxjs/Observer';
 import {Observable} from 'rxjs/Observable';
 
-import {MapsAPILoader} from './maps_api_loader/maps_api_loader';
+import {MapsAPILoader} from './maps-api-loader/maps-api-loader';
 
 /**
  * Wrapper class that handles the communication with the Google Maps Javascript

src/services.ts

@@ -1,5 +1,5 @@
 import {Injectable, Optional} from 'angular2/core';
-import {MapsAPILoader} from './maps_api_loader';
+import {MapsAPILoader} from './maps-api-loader';
 
 export enum GoogleMapsScriptProtocol {
   HTTP,