Added a note for a future improvement

Allow to choose which modules are compiled with raylib, if some modules are excluded from compilation, required functionality is not available but smaller builds are possible.

Allow texture loading with no data transfer (in case image.data = NULL)

raylib was using `stb_perlin.h` library to generate perlin noise, it seems that recently this library has been flagged as it could be infringing some algorythm patent. For security, it has been removed from raylib.

raylib modules have been slightly renamed to add some identity and note that they are independent modules that can be used as standalone separate parts of raylib if required.

The renamed modules are:
 - `core` -> `rcore`
 - `shapes` -> `rshapes`
 - `textures` -> `rtextures`
 - `text` -> `rtext`
 - `models` -> `rmodels`
 - `camera` -> `rcamera`
 - `gestures` -> `rgestures`
 - `core` -> `rcore`

All the build systems has been adapted to this change.

Following english rules, it should be singular name before Count.

* Fix tcc not finding emmintrin.h

This allows to compile raylib with tcc with no errors.

* Remove __TINYC__ check from stb_image.h

This will be placed under textures.c

* Move tcc check to textures.c

Avoiding to change stb_image.h

rlgl has been redesigned to avoid any dependency to `raylib` or `raymath`, all functions using some of those libs have been reviewed.
 - REMOVED: `Texture2D`, `Shader` structs dependency
 - REMOVED: `Vector3`, `Matrix` structs dependency
 - REMOVED: raymath functions dependency, all required math is implemented in rlgl
 - ADDED: `rlMatrix` custom rlgl type
 - ADDED: `utils.c`: `rlMatrixFromMatrix()` and `rlMatrixToMatrix()` for a safe conversion between raylib<->rlgl matrix types
 - ADDED: `rl` prefix to all `rlgl` structs
 - Other small tweaks here and there

* Implemented remaining 7/8 of ImageDrawLine

The existing code was correct for one octant, it now works for all 8
Added two internal functions, _ImageDrawLineHorizontal and _ImageDrawLineVertical, whithout which it would've been 4 times as much code.

* ImageDrawLine: Replaced 3 functions with 1

Removed both freshly added internal functions
Crammed it all into one

* ImageDrawLine shortened significantly using maths

Substituted X and Y, then wrote one abstract loop instead of 4 specific loops.
Lots of comments to explain what I'm doing for future maintainers.

* Now conforms with style conventions

Also reworded a comment to sound more... fomal.

RENAMED: GetTextureData() -> LoadImageFromTexture()
RENAMED: GetScreenData() -> LoadImageFromScreen()

ADDED: rlGetPixelFormatName()

RENAMED: GetCodepoints() -> LoadCodepoints(), now codepoint array data is loaded dynamically instead of reusing a limited static buffer.
ADDED: UnloadCodepoints() to safely free loaded codepoints
RENAMED: GetNextCodepoint() -> GetCodepoint()

Replaced: Returns -> Get

- Dividing by height instead of width results in missing parts of the image.