v0.9.4 - PrefixFs - fix prefixing Windows path

This release tackles the problem that occurs when you prefix a Windows path C:\H\I\J with another Windows path C:\A\B\

Previously you were not able to do that because you'd get the following file path which is invalid: C:\A\B\C:\H\I\J
This update fixes that behavior in a way that you are now getting such a path instead: C:\A\B\C\H\I\J
It's now misisng the : in the middle.