mdPopover: use mdPanel to create popover example

[ThomasBurleson]

Unlike tooltips which have minimal content, popups can have sophisticated, rich content and should also use a directional indicator pointing to the originating/requesting element:

Example #1:

Popovers are intended to have rich content that may be fully interactive.

[ThomasBurleson]

This is related to the Pull Request #1132.

[ThomasBurleson]

This specifications for this feature have been requested from the Material Design UX team. [response pending]

[epelc]

Would this be something you can click on links inside of or just for showing content?

[ThomasBurleson]

Popovers are intended to have rich content that may be fully interactive.

Tooltips, however, are:

• terse,
• read-only,
• transient,
• self-closing,
• single-line,
• informational constructs:

[ccarpediem]

So something a bit like a material version of DropJS (http://github.hubspot.com/drop/docs/welcome/)? If so I really like the idea. Covers that ground where you need a richer experience than a tooltip but without being as obtrusive as a dialog taking over your screen.

[ThomasBurleson]

@ccarpediem - yes.

[ajoslin]

This is just a <md-tooltip> with large content and a class added to it.

[stevenh77]

@ccarpediem Here is my implementation for material design: https://github.com/stevenh77/drop-ng

@ajoslin tooltips appear on hover whereas my implementation of a popover is activated on click.

Here is the bootstrap version: http://getbootstrap.com/javascript/#popovers

[ccarpediem]

@stevenh77 Looks good. One additional thing I think would be nice, is an optional parameter you could pass to define how it closes. Right now, it seems you need to click the button again to close it. I can see the option of just clicking anywhere on the screen closing it like tooltip and dialog would at least be nice option to have. Not sure which is the better default behavior.