Blender Git Loki

=== bugfix ===
filename and path issues:
[ #6107 ] Animation crashes when ouput folder does not exist
- using the Windows drive as default and only then degrading to the
Blender installation drive and then the first valid drive.
- in case of degrading added error message print to console to make it
transparent
[ #6106 ] fluids - no default path
- setting the default path to U.tempdir where Blender stores temporary files