Blender Git Loki

file operator cleanup
* the default properties of the file operator now only contain the "filepath", which means only the complete path to a file is returned.
* "filename" and "directory" has been added to the link/append operator - the only place it was used.
* sequence operators still work on the "files", which was custom property passed to the file operator anyway.
* have tested sequence loading, image loading and append/link - please report if there are any issues