- added support for cross-compiling with MXE (http://mxe.cc/)
- refactored CMake files, adding some options and moving definitions
to more suitable places
- added (very basic) SDL template in CApplication and CEngine
- split project into two targets: colobot_old (dependent on DirectX and WinAPI)
and colobot_new (dependent on SDL and OpenGL)
- moved sound.h/cpp to old/ and created new template in Snd namespace
- added platform-independent dialog boxes in app/system.h/cpp