Two new key presses

To speed up the game press Z, on release the speed changes to what it was.  (in TH this was done with W)

Moved transparent walls from a debug option to the main game. Press X and the walls become transparent and return to normal on release of the key. whilst the walls are transparent you cannot buy plots of land. this should fix issue 1470. Issue 1493 and Issue 1468 are also related