0.30.0

• Fixed problem trying to call QLineEdit.setPlaceholderText within Nuke.
• Gaffer.BlockedConnection now supports reentrancy, with the connection only becoming unblocked when the outermost block has been exited.
• Fixed bug which prevented selection using the up/down cursor keys from working in the PathChooserWidget.
• ImageGadgets now have a linear to srgb conversion applied when they are drawn. This means they now match the Image widget behaviour.
• PathChooserWidget and PathChooserDialogue now accept a new allowMultipleSelection argument to the constructor. Use the new PathChooserDialogue.waitForPaths() method to wait for paths selected in this way.
• VectorDataWidget has a new protected _createRows() method which may be overridden by derived classes to customise the addition of new rows. The PathVectorDataWidget implements this by displaying a dialogue where the user may select multiple paths to be added. This improves the parameter ui for PathVectorParameters.