0.56.0

• RenderManShader node now supports the use of annotations within the shader to define the node UI. Annotations follow the OSL specification for shader metadata.
• Added the GafferUI.Metadata class, which will be used to provide things such as node and plug descriptions for the generation of tooltips and reference documentation.
• Added a Prune node, for removing whole branches from a Scene (issue #70).
• The Menu class now supports the description field of menu items, displaying descriptions as tooltips.
• The Menu class now supports the passing of the menu to callables registered as subMenus.
• Added a “File/Open Recent” menu item (issue #118).
• Added the ability to reload RenderManShader nodes, updating them to reflect any changes to the shader on disk. This is done automatically on file load and can be performed manually at any time using the new button in the node editor.