Wheelchair Fixes

__Changes the following:__
 * Non-existant feet won't get blood-covered
 * Wheelchairs will now leave blood tracks similar to those from mulebots
 * Teleporting with wheelchairs now won't let you end up in space with the wheelchair teleporting to the targeted location
 * Occupant now actually gets movement penalty when hands are damaged
 * Stops wheelchair occupants from slipping (for now, might add a hilarious change later)
 * Changes 'clash' into 'crash'
 * Running over cat won't glitch out the everything
 * Occupants will now be able to access the strip menu and use camera consoles properly
 * Clicking somewhere while sitting in the wheel-/officechair will now face the player into the clicked direction

Now that I touched teleportation code, I saw that test-firing doesn't do anything at all - might change that in this PR as well so people stop ending up in space after test-firing, otherwise it has no use.
Wouldn't it make limbless people movable?