#342 Separate user Mnets

[Oscar Haeger]

On windows all Mnet-related things are put in
c:\program\mnet or similar.

It would be a good thing (tm) if we could separate the
program from the user data so that many users could run
a few different nodes on the same machine.
This is already done in Linux where the user-data is in
.mnet/

I suggest we put the user data in c:\documents and
settings\$user\mnet or similar