Improvements of Material Preview

I have fixed the problem with Alpha in the preview that showed the rough glass material as black. This was probably caused by the recent Blender alpha changes.

I have also increased the brightness of the checker pattern in the background to see better the glass effects, etc.
Merge pull request #1 from DavidBluecame/experimental-dt

Improvements of Material Preview
Fix for preview crash
Exporting normals directly from blender to increase the consistency of the rendered geometry and resolve reflect/refract artifacts
Added git ignore for python precompiled files, just a convenience adition to the repo
Premultiply forced enabled, not optional anymore
Look & Feel changes for more visual clarity on general settings, checkboxes -> toggle buttons
Depth Map directly into blender buffers
Version bump 1.5.0-Stable
Additions to have a consistent z-buffer rendering into blender
Merge pull request #14 from DarkTide/master

Version bump, and some other fixes