supertux/mk/msvc

WARNING This msvc build is totally unsupported and experimental! This is for
people who know what they are doing. Please don't annoy us with questions if
you don't know:
- how c++ works and how to fix smaller errors yourself
- what an include directory is
- how to make a windows application find .dll files
- what a .lib file does

In general fix the stuff yourself, you probably know msvc++ better than me
anyway. Apart from that patches which keep these project files running are
always welcome ;-)