Version 0.12.1.0

Core

• Fixed hangs introduced in 0.12.0.0. These were seen when stopping
  Appleseed renders and when ganging plugs in Caribou.
• Fixed thread-related crashes introduced in 0.12.0.0. These have not
  been observed in the wild, but caused intermittent failures in the
  unit tests.

UI

• Improved error messages output by OpDialogue.
• Fixed unwanted auto-expansion in SceneHierarchy panel.

Scene

• Added current scene location to error messages emitted by SceneProcedural.
• Reduced memory usage for sets by 10%.
• Optimised set computations. This reduces globals computation time for
  a complex production scene by 60%.
• Fixed PathFilter wildcard matching bug.

OSL

• Added metadata presets support for color and point parameters.

API

• Added iterators to GafferScene::PathMatcher.
• Added GafferUI.EditMenu.selectionAvailable() method.