Blender Git Loki

New command line argument to specify render engine

-E <engine>

-E help: lists all available engine and then quits. (blender window might flash open and then disappear. io python scripts need to be read for all engine, so we have to load interface and not do that before like other help options).

When run after -b, only builtin engines are available because of the python scripts not being read correctly bug.