Sdl mouse options & CBM probability travel

Mouse hiding options (always hidden; always shown; show on mouse movement and hide on key input) and a new CBM that lets you go through walls (because I pushed before reading the guide that said to make a separate branch :p). CBM probability travel has the same rarity/installation difficulty as CBM time dilation and costs 10 bionic power per impassable tile traversed; balanced? I put it with the super-soldier CBMs in mapitems.cpp.