Fix build failure introduced in 2a913b6587

- Mesh, Shader, Material structs have been reviewed to minimize size when passed by value, all required code has been reviewed.
 - GetCollisionRayModel() reviewed to avoid pointer, not required because model is not modified inside the function
 - UnloadMesh() reviewed, pointer not required
 - CheckCollisionRay*() parameters name reviewed

ADDED: GetPrevDirectoryPath()

Free texturePath in LoadGLTF()

* Fix loading multiple animations from .iqm file

* Fix memory leak in models_animation example

* Added export instructions to the animation example

* use raylib free

* include <stdlib.h> to appease the travis CI gods

* replace tabs with spaces

Added in a check for x86 and x86_64 branches of android

Added in $(OS) checks to see if we're running on windows or *nix

Added a default location for android ndks and sdks at /usr/lib/android

* Update year of copyright notices

* Fix mistake in comment

* Fix typo ("algorythms")

* Replace tabs with spaces

* Remove trailing whitespace and fix mistake in comment

* Fix ExportImageAsCode missing comment rectangle corner

* Replace tab with spaces

* Replace tabs with spaces

Object Pool Changes:
-- changed 'size' member name of 'union ObjInfo' to 'index' to better name its purpose.
Memory Pool Changes:
-- Added memory node buckets to store and allocate smaller, more frequent byte sizes.
-- Replaced 'memset' call to deinitialize free list data with NULL and 0 assignments.
-- Removed some no-longer-needed commented-out code.
-- Changed insertion sort code to put the largest size at the tail rather than the head.
-- Made certain pointer variables as constant pointers.

* Patched potential bug when defragging.

Patched a potential bug concerning the '__RemoveNode' function as, when removing certain nodes that are either at the head or tail, it can yield a free list node of size 0 bug as the previous node was removed and its size was set to 0 but not fully removed from the other nodes.

* A few more potential bug patches.

- Updated Makefile with new examples

Reviewed latest PR to also consider OpenGL 1.1 extension support (unprobable).

Now, multiple music parameters are exposed to the user!

Not working yet... :(

It can break building on that platform...

Completely useless and actually buggy!

Changes:

 - Font structure has been redesigned, CharInfo structure contained character rectangle within font texture, it has not much sense, considering that it was an information relative to the font atlas generated and not the character itself, so character rectangles have been moved out from CharInfo to Font.
 - CharInfo included a data parameters to contain character pixel data (usually grayscale), generated on TTF font generation. It was inconsistent with other fonts types, so, now CharInfo includes directly an Image of the glyph.
 - REDESIGNED: GenImageFontAtlas(), additional recs parameter added, loaded and filled inside the function to export atlas characters rectangles, instead of silently modify the input CharInfo data.
 - REVIEWED: ImageTextEx(), funtion retrieved the font atlas image from the GPU, that was slow and problematic in several platforms. Now it uses directly the CharInfo image. Support for unicode codepoints has also been added.
 - REDESIGNED: ImageDraw(), now it includes an additional parameter, the color tint, not only it could be useful for several situations but also function signature is more consistent with similar functions.
 - ADDED: ImageFromImage() to generate a new image from a piece of another image.
 - REVIEWED: GetNextCodepoint(), renamed parameters to be more clear.

Also all examples and games that were affected by those changes have been reviewed.

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.