visualgst: Show contex debug informations in GtkDebugger

Show the arguments and temporaries in the debugger.

2013-08-20  Gwenael Casaccio  <gwenael.casaccio@gmail.com>

	* Extensions.st: Move some extensions to Debugger/Extensions.
	* Debugger/Extensions.st: Moved extensions.
	* Debugger/GtkStackInspectorView.st: Support debug information.