release 0.61 on Windows

[JAZEIX Johnny]

Hi,

following yesterday work, I finally managed to compile a windows version 
with box2d for both 32b and 64b

http://gcompris.net/download/qt/windows/gcompris-qt-0.61-win32.exe

http://gcompris.net/download/qt/windows/gcompris-qt-0.61-win64.exe

For balancebox, there is a bug (the ball is behind the points to access) 
but it's fixed on the current master.

We are a step closer making it the official version!

Feel free to test and report any bug.

Johnny