Add an icon and executable information to the colobot.exe when build in MXE
Revert "Include SDL.h in main.cpp to make sure the main loop is SDL's main loop"

This was the wrong fix for the problem.

This reverts commit f31a570d96e1a0ee28baecefa18b7e8c586c201c.
On MacOSX, use SDL_Main
Merge pull request #245 from OdyX/dev-platform-fixes

Platform fixes (Windows Icon and Mac OSX SDL_Main fix)