Suppress deprecation warning and Implement New GDK+3/GTK+3 API

* Various API obsoleted
* Implement New GDK+3/GTK+3 API(but partially GTK+3 part)
* add deprecation warning to deprecated.rb

This changes too big for me, I cannot confirm this changes to fit Ruby-GNOME2 way.
So, I decide that I send pull request nevertheless I can push master directly. 

Because it would be easy to code review when it send pull request....