Fixed Widget.bound() on OS X.
Adding new Gaffer logo graphics
Re-fixed Widget.bound() for Linux.

Hopefully it will still work on OS X now.
Adding Window set/getIcon and setting GafferLogoMini as the default icon.

Eventually we can create derived icons for each utility app to distinguish if necessary.
Added closure parameter support to OSLShader.
Merge pull request #623 from andrewkaufman/logo

Added our new Logo
Merge pull request #616 from johnhaddon/osxWidgetBoundFix

Fixed Widget.bound() on OS X.
Merge pull request #624 from johnhaddon/oslClosureParameters

Added closure parameter support to OSLShader.
Implemented highlighted drawing for ColorSwatch.
Added ColorSwatchPlugValueWidget.

This displays a colour plug purely as a colour swatch, without the numeric fields. It supports the dragging of the colour from the swatch to other plugs and the script editor. The ColorPlugValueWidget now uses it for its swatch, so that too supports dragging now.

Fixes #625.
Added Style::changedSignal().

This is emitted when some aspect of the style has been modified, and is used by the Gadget to emit Gadget::renderRequestSignal(), triggering a redraw.
Merge pull request #627 from johnhaddon/colorSwatchPlugValueWidget

Color swatch plug value widget