Arnold 5.3 features and operators

[JenusL]

New Features

• Operators (on passes, not on procedurals yet)
• GPU Rendering
• New Adaptive AA
• Visible area lights
• standard_surface changes
  • Coat Anisotropy added
  • Transmission Extra Roughness can have negative values
• New uv_projection shader
• New matrix_interpolate shader
• Autobump Visibility
• Ignore Motion and Instantaneous Shutter

SItoA specific enhancements

• General support for Shader Parameter Arrays
• closure shader is now bypassed and no longer exported to Arnold. This was a necessity to get GPU to work. But this is actually a very good thing and it will also make .ass files from Softimage more compatible with other DCCs.
• New Enlarge buckets in progressive IPR option that makes the buckets larger when rendering progressive (only in Render Region). See #67 for more information.
• 4 new tests in testsuite for Operators, Visible area lights, Autobump visibility and GPU rendering

Known Issues SItoA crashes when trying to get a license from Autodesk License Manager (FlexLM). RLM licenses work fine. See #74 for details. I found a bug with the new autobump visibility and have reported it to the core team.

[JenusL]

Just added 3 new tests and it all passes the testsuite. So I'm pretty happy with where this is now and I would like to release this soon. Maybe after the next core release. @sjannuz Any idea when that is? When you find the time, maybe you could build it on Linux as well and @knekke could test i a little if he has time? 😉

[knekke]

Just let me know when a Linux build is ready, and I will do some happy testing!

[JenusL]

Arnold 5.4 is released tomorrow so lets merge this PR so I can start work on 5.4.