Using `misc/scripts/fix_headers.py` on all Godot files.
Some missing header guards were added, and the header inclusion order
was fixed in the Bullet module.
After discussing with @reduz and @akien-mga it was decided that we do
not allow assignments or declarations in if statements. This PR removes
the instances of this I could find by automated means.
Currently we rely on some undefined behavior when Object->cast_to() gets
called with a Null pointer. This used to work fine with GCC < 6 but
newer versions of GCC remove all codepaths in which the this pointer is
Null. However, the non-static cast_to() was supposed to be null safe.
This patch makes cast_to() Null safe and removes the now redundant Null
checks where they existed.
It is explained in this article: https://www.viva64.com/en/b/0226/
Now the shape in the physics server is unbound only when it's unparented from its body, because if it's unbound when just exiting the tree, a later readd would have the body shapeless in the server.
It's the same currently being done in 2D physics.
Fixes#10074.
-Added new 3D stream player node
-Added ability for Area to capture sound from streams
-Added small features in physics to be able to properly guess distance to areas for sound
-Fixed 3D CollisionObject so shapes are added the same as in 2D, directly from children
-Fixed KinematicBody API to make it the same as 2D.
