A connection appears (but not with drag and drop).
Beginning of the connections with QML drag and drop
First step with QML Drag and drop to fix the connections.
MainWindow and GraphEditor layouts
remove useless code
Canvas fix
fix graph toolbar
graph: change the way we manage connections
Fix for images' urls (windows)
Proper way to change properties with state. And property keys used to secure the drag and drop
First step to detect a drag an drop of a node over a connection
Graph: fix connections update

And fix graphEditor and player layouts (using implicitWidth)
Merge branch 'dev_graph' of github.com:buttleofx/ButtleOFX into dev_graph

Conflicts:
	buttleofx/gui/graph/qml/Graph.qml