It appears that some time ago users were supposed to be able to include the playback of sound effects in their animations by placing keys on the "playing" property. Back then the key frame editor took the value of the checkbox in the property_editor.
Somewhere / Sometime this behaviour changed and the key frame editor is now reading the actual value from the object instead of relying on the property editor.
This commit introduces a fake active field that is returned when reading the playing property in the editor. While the actual active flag is changed when playback is finished the fake one will stay the same thus allowing the user to take their time with setting the key in the animation editor.
Found via `codespell -q 3 --skip="./thirdparty,./editor/translations" -I ../godot-word-whitelist.txt`
Whitelist consists of:
```
ang
doubleclick
lod
nd
que
te
unselect
```
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/
