Changes:
- Rename few methods/property and group them in the editor when it's possible
- Make MotionResult API consistency with KinematicCollision
- Return a boolean in move_and_slide if there was a collision
- New methods:
- get_floor_angle on CharacterBody to get the floor angle.
- get_angle on KinematicCollision to get the collision angle.
- get_last_slide_collision to quickly get the latest collision of move_and_slide.
PhysicsBody now has methods move_and_collide/test_move and needed
properties for these methods: safe margin, locked axes (3D only).
Moved collision_exceptions from StaticBody to PhysicsBody for 3D
(same as 2D, and conforms to documentation).
RigidBody doesn't have test_motion method anymore, it's now redundant
with PhysicsBody.test_move.
