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.
This commit implements a big update of rlgl module, intended to optimize some parts. This change could break some code bases... hopefully not, but it could.
The BIG changes to the module are:
- Replaced LINES-TRIANGLES-QUADS buffers by a single one, now all vertex data is accumulated on a single buffer and managed with registered draw calls. LINES-TRIANGLES-QUADS could be used the same way as before, rlgl will manage them carefully. That's a big improvement of the system.
- Support multi-buffering if required. Just define MAX_BATCH_BUFFERING desired size (currently set to 1 batch). Should be enough for most of the situations.
- Removed temporal accumulative buffers for matrix transformations, now transformations are directly applied to vertex when on rlVertex3f()
- Reviewed rlPushMatrix()/rlPopMatrix() to be consistent with OpenGL 1.1, probably I should remove that ancient behaviour but... well, it was not consistent and now it is.
- Minor tweaks: LoadText(), I broke it in last update... also multiple comments reviewed.
- TODO: MAX_BATCH_ELEMENTS checking should probably be reviewed... done some tests and it works but...
