Blender Git Loki

Improvements to File->External Data->Make Paths Relative & Make Paths Absolute,
made when testing peach blend files wont have path issues when sent to the renderfarm.
* log failed path conversions
* clean the path so //foo/../foo/ is removed (not sure why but some peach files had this problem)
Also added a function to util.c
BLI_cleanup_file, same as BLI_cleanup_dir but dosnt add a slash at the end.