Changes : Update following release of 0.53.5.0
Changes : Update following release of 0.53.5.0

This includes the changes currently on master that are destined for release in 0.54.0.0. It's important to update these at the same time as the changes for the current maintenance branch, as otherwise it's easy to lose track.

> Note : This does not mention either the startup config documentation or the SetVisualiser node, as the former broke the build and it's not yet clear which version the latter will land in.

GafferHQ/gaffer,GafferHQ/gaffer,hradec/gaffer,hradec/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,boberfly/gaffer,lucienfostier/gaffer,andrewkaufman/gaffer,appleseedhq/gaffer,ImageEngine/gaffer,johnhaddon/gaffer,johnhaddon/gaffer,ImageEngine/gaffer,andrewkaufman/gaffer,appleseedhq/gaffer,hradec/gaffer,lucienfostier/gaffer,johnhaddon/gaffer,hradec/gaffer,boberfly/gaffer,hradec/gaffer,GafferHQ/gaffer,appleseedhq/gaffer,boberfly/gaffer,andrewkaufman/gaffer,appleseedhq/gaffer,ImageEngine/gaffer,lucienfostier/gaffer,johnhaddon/gaffer,ImageEngine/gaffer,lucienfostier/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,boberfly/gaffer