Fix :Vopen tab complete of a/b on Windows
Fix :Vopen tab complete of a/b on Windows

Closes #70.

wyli/vimsettings,wyli/vimsettings,ccheetham/myenv,wyli/vimsettings,ccheetham/myenv,ccheetham/home,wyli/vimsettings,ccheetham/home,ccheetham/myenv,ccheetham/home