Disabled signed/unsigned warnings like for GCC/Clang
(warning C4018: '>=': signed/unsigned mismatch).
Fixes the following MSVC 2017 warnings:
```
core\image.cpp(999): warning C4804: '>': unsafe use of type 'bool' in operation
core\io\compression.cpp(178): warning C4334: '<<': result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?)
editor\doc\doc_dump.cpp(226): warning C4334: '<<': result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?)
scene/resources/material.h(289): warning C4334: '<<': result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?)
scene/resources/material.h(298): warning C4334: '<<': result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?)
editor\editor_themes.cpp(379): warning C4805: '==': unsafe mix of type 'int' and type 'bool' in operation
```
This allows more consistency in the manner we include core headers,
where previously there would be a mix of absolute, relative and
include path-dependent includes.
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.
-Fixes to unwrapper (remove degenerates), makes Thekla not crash
-Added optional cancel button in EditorProgress
-Added function to force processing of events (needed for cancel button)
Schlick's approximation and GGX are orthogonal concepts.
Furthermore, it's usage so far has been inconsistent: we don't even use it with anisotropic SchlickGGX, and Burley (Disney) diffuse does use it while its name doesn't indicate it.
The use of Schlick's approximation in Burley and GGX is an implementation detail and doesn't need to be reflected to the namig.
I can show you the code
Pretty, with proper whitespace
Tell me, coder, now when did
You last write readable code?
I can open your eyes
Make you see your bad indent
Force you to respect the style
The core devs agreed upon
A whole new world
A new fantastic code format
A de facto standard
With some sugar
Enforced with clang-format
A whole new world
A dazzling style we all dreamed of
And when we read it through
It's crystal clear
That now we're in a whole new world of code
Rémi Verschelde
Juan Linietsky
JFonS
Alex Roman
luz.paz
Ferenc Arn
Hiroshi Ogawa
Maxim Sheronov
TwistedTwigleg
George Marques