0.24.0

• ParameterisedHolder now correctly loads an instance of the held class following serialisation.
• ParameterisedHolder::setParameterised() and OpHolder::setOp() now accept an optional keepExistingValues parameter which defaults to false. Passing true preserves existing plug values in preference to the values in the incoming Parameterised object.
• TabbedContainer now allows the addition of a custom Widget to the top right corner using the setCornerWidget() and getCornerWidget() methods.
• Fixed a bug which meant that the ButtonEvent::line field was incorrectly transformed when delivering events to Gadgets.
• Fixed tab sizing issue on OS X.
• Fixed crashes in ObjectParameterHandler triggered by plugs with null values.
• Added enterSignal(), leaveSignal(), dragEnterSignal() and dragLeaveSignal() methods to Gadget. Nodules now highlight themselves when entered using this new functionality.
• Fixed GafferUI to work with qt 4.6 as well as 4.7.
• Gaffer can now be run embedded in Nuke.