Merge.
Clean some code.

Clean the most part of the display on console.
Add CmdDeleteConnection.

To do this cmd : clic on the clips between the 2 nodes of a connection.
Still a bug when redo cmdDeleteConnection.
Fix bug about undo redo when create and delete connection.
Merge branch 'develop' of github.com:buttleofx/ButtleOFX into develop

Conflicts:
	buttleofx/gui/graph/graphWrapper.py
	buttleofx/gui/graph/qml/Node.qml