image are now homogenous
- Layout improvements (keyboard editor)

- Bug fixing (host)
- The host's keyboard choosing panel is now linked to a specific viewmodel that implements INotifyPropertyChanged.
Editor : some layout & ergonomics improvements.
Merge branch 'keyboard-editor-layout-ref' into develop
Editor : layout improvements, we can now move keys with up,down,left,right

Moves are handled via RegisterHotKey, which are global hooks.
I'll try the MessageFilter API next time..