0.7.0

• Can now derive from ScriptNode in python and override acceptsChild etc as expected.
• ScrolledContainer and viewer classes have now been ported to the Qt based GafferUI.
• Added a GafferUI.Image class for displaying images in a widget.
• GafferUI.Menu class now supports checkBox menu items again.
• GafferUI.CheckBox widget now displayed with a tick rather than a blank yellow box.
• CompoundNumericPlugValueWidget has now been ported to the Qt based GafferUI, providing uis for V2f, V3f, V2i and V3i plug types.
• GafferUI.Widget derived classes may now pass a GafferUI.Widget instead of a QtGui.QWidget instance to the base class constructor. This makes it possible to develop a wider variety of custom widgets without resorting to Qt APIs.