Google and Yandex tile-layers changed

1. An event "MapObjectInitialized" (with map-object as its argument)
added to "_initMapObject" of Google and Yandex layers, so the code that
uses plug-ins will be able to use their JS API through their
map-objects.
2. Yandex map type initialization changed (see explanation in comments)
3. Yandex map-object creation completed (see explanation in comments)
Update Google.js

Stripped comment about the 'MapObjectInitialized' event.
Update Yandex.js

1. Huge comments stripped.
2. Added backward compatibility of the map type assigning (for the short names of map types).
Merge pull request #124 from SeregaMatin/master

Add MapObjectInitialized envent for Google and Yandex + Map type initialization changed and map-object creation completed for Yandex