Comment 7 for bug 1202101

As there were a lot of changes I did a new compilation test on Windows with BZR revision 6651 now:
unfortunately you have to change the title of this bug report again, because we do have 2 compiler errors again. ;-)

Please first apply attached patch to following compiler warning:
- unary minus on unsigned values and overwritten warnings by specifying the right compiler option in the CMake file for the VS compiler and
- removing not referenced variables in the code.