This simplification will allow the usage of `rshapes` as STANDALONE mode in a future. Only a small set of `rlgl` functions are required and they can be "more" easely replaced if no `rlPushMatrix()`/`rlPopMatrix()` are involved.

More simplification planned for the future, maybe the textures dependencies.

Updated version to `rlgl 4.2`

* Update raylib.h

* CheckCollisionPointPolygon()

* typo

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.

Co-authored-by: SAOMDVN <saomdvn@users.noreply.github.com>

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.

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

Co-authored-by: Lambert Wang <lambert.ww@gmail.com>

Co-authored-by: Simon <simon@frithrah.com>

Use fabsf() instead of abs()

* CheckCollisionPointTriangle

* New feature proposal to existing collision detection routines.
It checks if point [point] belongs to line created between two points [p1] and [p2] with defined margin in pixels[threshold].
1693

rlgl module has been completely redesigned to move Mesh/Material structures to [models] module. Still some work to do, broken elements:
 - [models] OpenGL 1.1 mesh rendering: DrawMesh()
 - [models] Mesh Instancing: DrawMeshInstanced()
 - [models] Stereo rendering: DrawMesh()
 - [models] GL_FLOAT, GL_UNSIGNED_INT exposed
 - [models] GenMeshCustom()
 - [rlgl] GenTexture*() functions removal?

Function analyzed using RenderDoc. It's a complex function and could require many triangles for the corners but it seems overall it's quite optimized!

- The vertices did not map to where I expected causing rotation to be
off by 90 degrees. I reorganized the vertices making it easier to
reason about which fixes this.
- The order for drawing is now topLeft, bottomLeft, bottomRight,
topRight.

- Some rlgl functions have been moved to core
 - Some functions have been made internal to rlgl
 - rlgl functions prefixed with rl*()

* Optimize DrawTexturePro and DrawRectanglePro transformations
- Add check so rotation is only applied if rotation != 0.0f.
- Replace matrix usage by calculating the vertex data directly.

* Fix error with windows build and trim whitespace

Co-authored-by: Simon <simon@frithrah.com>

* Fixed DrawLineEx

Corrected the issue https://github.com/raysan5/raylib/issues/1596

* Removed raymath dependency for DrawLineEx