You cannot sit in air anymore.
I just changed the Player so that it will keep track of the current
platform its on. The platforms do now have two new Methods, one is to
indicate if a platforms collision should get applied and the other one
to indicate if the player should get moved if the platform moved.
The player will fall if the current platform returns that collision is
not to be applied anymore and should get moved with moving platforms,
wich are not yet implemented.