Batch renders now abort on license fail

Arnold now aborts if there is a license error in a batch render. The option abort_on_license_fail is now true by default, and applies to batch renders only. This means you don't have to check rendered image sequences for watermarks. Interactive renders do not abort, and have a watermark on license fail as usual. The environment variable ARNOLD_FORCE_ABORT_ON_LICENSE_FAIL overrides this default behavior

• 0 = batch and interactive render with watermarks on license fail
• 1 = batch and interactive abort on license fail). (ARNOLD-13024)