Auxiliary Files support

This release adds support for submitting auxiliary files with the Deadline submission and a few minor fixes and additions to progress reporting and errors.

The auxiliary file directory is set by Deadline as an environment variable and can be referenced in a Gaffer script using normal string substitution format, for example ${AUXFILEDIRECTORY}

Note that Deadline copies all auxiliary files, regardless of the source directory, to a single directory, losing their directory tree.

• added plug on the Deadline Dispatcher for an array of file names to include in the Deadline submission
• Gaffer Deadline plugin adds an environment variable called "AUXFILEDIRECTORY" that scripts can use to reference these files
• Handle errors from Gaffer and fail the job
• Handle VRay render progress updates and include those in the job progress
• add support for Gaffer 0.55.2.1

GafferDeadline 0.50.0.1

Small bug fix for GafferDeadlineUI that was preventing GafferDeadline from creating its plug on task nodes.

Release 0.50.0.0

This is the first release of the GafferDeadline dispatcher to send Gaffer node graphs to Deadline!