[Implemented] Get the force, impulse velocity of an entity

[DarkDragon]

Hello,

I just noticed, that you can't get the force, impulse and velocity of an entity. This is necessary, as I don't want the player to move faster than light though the levels! You need to be able to specify the maximum impulse/force/velocity somehow. If we can't we must live with either lightspeed players or players which can stop in midair to move into other directions.