Renamed Server/ to server/

-Renamed the folder
-Updated buildDXB.sh accordingly
Updated .gitignore

-Updated .gitignore so that it doesn't gitnore build/DXBall.pro
-Updated DXBall.pro so that it the main executable for DXBall is called
DXBall_exe instead of just DXBall
-Updated buildDXB.sh so that it builds Server as Server_exe instead of
just Server
-Updatede .gitignore to ignore everything ending with _exe ( which means
	it'll ignore all executables )