0.56 series: New features recap

As adoption of Gaffer 0.56 or later is contingent on moving to Arnold 6, we appreciate it may take a little longer to switch production shows over. People may also move directly to the the upcoming release of 0.57.
This post contains a quick recap of the main artist-facing changes in the 0.56 series for those moving up more recently.
Features
- Deep image support: GafferImage now supports deep image compositing, new 'Deep' prefixed nodes provide deep data specific operations.
 - MergeScenes: This new node allows the hierarchies of two independent scenes to be merged.
 - ShuffleAttributes, ShufflePrimitiveVariables: These nodes allow a locations attributes and primvars to be renamed/copied.
 - Lighting texture visualisation: The viewer now supports the visualisation of light textures and gobos, along with more general improvements to light and camera visualisation.
 - Crop 2D + improved UX: The Crop Window Tool can now be used from the image view and is easier to edit.
 - Catalogue columns: The Catalogue now shows the status of a render and supports custom columns, to integrate shot data, etc.
 
Improvements
- Backdrops: Context variables can now be used in title/descriptions.
 - Transform and Camera tools: New modifier keys to change movement precision.
 - Set Expressions: 
inandcontainingoperators allow more efficient sets and more flexible filtering. - OSL: Added example scenes for OSL nodes, see 
Help>Examples>Compositing/Scene Processing. - Instancer: Much more flexible options for choosing which locations are used as sources.
 
💡
0.56 introduced some breaking changes:
Bug fixes to the ImageReader, ImageWriter and Resize nodes mean that the generated images will differ substantially in some circumstances. 
The following nodes have renamed plugs and/or added features, such that files saved in 0.56 are not fully compatible with 0.55 : Instancer, OpenGLAttributes, Light and Camera. 
See the full release notes for more details.
Further reading:
- Gaffer 0.56.0.0 release notes
 - Gaffer 0.56.1.0 release notes
 - Gaffer 0.56.2.0 release notes
 - Blog post: Crop window tool -2D
 - Blog post: Transform/Camera tool improvements
 - Blog post: New set expression operators
 - Blog post: Area light visualisation
 - Catalogue custom column API