Update 0.8.51

Cathedral level: significant optimization of the level.
Minor changes to the Cathedral level.
Fixed a bug where arrows could not be used to take control of satyrs, and changed the skill description accordingly.
Slightly improved physics of satyrs (under certain circumstances bullets were flying through the satyr)
Island: fixed a bug with texts on information screens.
Island: building vertical wind turbines is now allowed only slightly further apart.
Fixed internal bugs in the bow arrows.
Fixed a bug where the camera sensitivity setting did not work.