MEDIUM: Fixed creation of a delete action in deletion scheme
IN PROGRESS - issue OPENFLEXO-820: Update Edition Pattern Graphical
Interface to make it more ergonomic 
https://bugs.openflexo.com/browse/OPENFLEXO-820
EditionPatternPreviewDrawingView preferred size is based on the bounds
of each components contained and with a minimal size of 300x200px
MEDIUM: Fixed incorrect layout constraint on button panel
LOW: Prevented NPE
LOW: Added "locationInDrawing"
LOW: Prevented NPE