events for add & removing widgets

[xLink]

any chance you could add events for when a widget gets added, and one for removal of a widget too

[troolee]

Sure, I can do this.

[jffaust]

While playing with the code for add and remove, could you check this issue.

Thanks !

[radiolips]

Duplicate of #54. Emitting events for adding and removing widgets will be completed for v0.2.5 and the original ticket will be updated when the feature has been completed.