Make separation ray shapes work properly in move_and_slide, wihtout the
specific code in CharacterBody like before.
Now most of the logic is handled inside the physics server. The only
thing that's needed is to use ray shapes only for recovery and ignore
them when performing the motion itself (unless we're snapping or slips
on slope is on).
Infinite inertia:
Not needed anymore, since it's now possible to set one-directional
collision layers in order for characters to ignore rigid bodies, while
rigid bodies still collide with characters.
Ray shapes:
They were introduced as a work around to allow constant speed on slopes,
which is now possible with the new property in CharacterBody instead.
For the time being we don't support writing a description for those, preferring
having all details in the method's description.
Using self-closing tags saves half the lines, and prevents contributors from
thinking that they should write the argument or return documentation there.
Fixing by applying the movement in two steps, first the platform
movement, and then the body movement. Plus, add the platform movement
when we are on_wall.
MODE_DYNAMIC instead of MODE_RIGID
MODE_DYNAMIC_LOCKED instead of MODE_CHARACTER
No more special case for sleeping behavior for MODE_DYNAMIC_LOCKED
(MODE_CHARACTER was forcing the body not to sleep, which is redundant
with can_sleep and wasn't done in Bullet).
