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.
Rename user facing methods and variables as well as the corresponding
C++ methods according to the folloming changes:
* pos -> position
* rot -> rotation
* loc -> location
C++ variables are left as is.
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/
-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.
