Fixes #899, which made apparent three issues with how static libraries
are handled in raylib-config.cmake:

- XPREFIX is set before pkg_check_modules, which causes a duplicate
  STATIC in variables, e.g. PC_RAYLIB_STATIC_STATIC_.*
- raylib_static is searched for, but no library exists with that name
- raylib_LDFLAGS isn't populated properly

This commit fixes these.

Added security checks in case provided image to functions hasn't been properly loaded... just to avoid program crashes.

This module has been completely reviewed, old structures still contained OpenAL useless data, a full module revision. Some of the changes:
 - Redesigned internal MusicData structure
 - Exposed MusicStream structure data
 - Reviewed AudioStream structure
 - Redesigned Sound structure

Still some work to do...

It needs to be freed

L235 - Increased the memory threshold size so that we can further reduce fragmentation by allocating memory blocks that is close to the requested size by 16 bytes.

* Submitting rmem memory and object pool module

* changed 'restrict' to '__restrict' so it can compile for MSVC

Added `const` to parameters for `MemPool_Realloc`

* Update and rename mempool README.txt to mempool_README.md

* Update mempool_README.md

* Update mempool_README.md

* Update and rename objpool README.txt to objpool_README.md

* implementing changes

* updating header for changes.

* forgot to change _RemoveNode to __RemoveNode

* removing l

* removing l

* Updating documentation on MemPool_CleanUp function

* Updating documentation on ObjPool_CleanUp function

* changed *_CleanUp function parameter

Replaced `void*` pointer to pointer param to `void**` so it's more explicit.

* Updating header to reflect changes to the *_CleanUp functions

* A single change for the mempool and a patch for the objpool.

Object Pool Patch: if you deplete the object pool to 0 free blocks and then free back one block, the last given block will be rejected because it was exactly at the memory holding the entire pool.
Mempool change: switched memory aligning the size from the constructor to when allocating.

- Capital letters at beginning
- for loop spacing and brackets
- Functions naming for consistency
- Example following examples template
- Other tweaks

* added multi channel sound replay to raudio
added -fPIC to Makefile for Linux
added simple lighting and audio multi channel to examples Makefile

* not properly reporting audio buffer pool size...

Renamed internal function for consistency with similar functions.

Fix vertex padding not zeroed for quads

Do not stop update/draw on window minimized

WARNING: SetConfigFlag() was reviewed to support int flags

Reviewed comments

Keyboard patch

Update

Update Makefile