This commit does the following:
* fix the keyboard logic (which now fully works), add support for vertical mouse wheel events ;
* make the rendering a lot more efficient, by using RDP damage information to refresh only the relevant part of the buffer ;
* fix two race conditions. wlfreerdp should not crash anymore now ;
* fix shm_open() and shm_unlink() calls ;
* improve the code style.
Signed-off-by: Manuel Bachmann <tarnyko@tarnyko.net>