Handle JS API initialization

[RopoMen]

Hi,

Could you add support for init of JS API's?

1. YouTube video is about to embedded and JS API is enabled in settings.
2. Your 'embedVideo' directive notices this setting and calls 'JSAPIInitializer' -service, for example 'JSAPIInitializer.initYouTube(callback_when_ready)'
3. service would inject YT JS API javascript in to and listen YT onready callback function.

This would be 'lazy' load of YT API (and others) and I don't need to handle that inject. I do not like the idea that I need to add all JS files at the :<