Update zync_maya.py for VRAY 3.0 API

vray now outputs None type when querying Material Select Elements and results are empty. Random cleanup otherwise.
rolling back file name checks

Though these checks also both return as false, and so can be checked that way, certain side cases may slip through... such as files named 0
Merge pull request #3 from justin-wood/master

Minor updates to support Vray 3.0 API.