<bugfix>Fix issue with persistent paths in Windows</bugfix> <ticket>#718</ticket>
<bugfix>Fix issue with persistent paths in Windows</bugfix>
<ticket>#718</ticket>

Turns out that dulwich isn't a fan of backslashed paths.  Switching the path separator to a forward slash seems to fix issues on Windows.

vistrails/packages/persistence/repo.py:
  - GitRepo._stage: replace os.path.sep in filename if it isn't a forward slash

VisTrails/VisTrails,celiafish/VisTrails,minesense/VisTrails,Nikea/VisTrails,Nikea/VisTrails,minesense/VisTrails,VisTrails/VisTrails,hjanime/VisTrails,minesense/VisTrails,celiafish/VisTrails,Nikea/VisTrails,VisTrails/VisTrails,celiafish/VisTrails,hjanime/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,minesense/VisTrails,hjanime/VisTrails,celiafish/VisTrails,hjanime/VisTrails,minesense/VisTrails,hjanime/VisTrails,Nikea/VisTrails