Added struct Vector4 for convenience

When UnloadModel() --> UnloadMaterial(), avoid unloading default shader (if used) and avoid unlaoding default texture (if used), that data is managed by raylib internally. The question is... should UnloadModel() also UnloadMaterial()?

Apparently, before macOS Sierra version, clock_gettime was not available, using MATCH timming system instead

Found by grepping for '(blob|tree)/develop'.  See #443 for more information.

See #443 for more information.

Integrate develop branch (LAST INTEGRATION)

Supported UTF8 range equivalent to [128..255] (80h..FFh)
Exposed and renamed text function GetGlyphIndex()
Renamed spriteFont parameter name to simply font
Small security check on transmission mission ending screen

Support string replacing to generate newspaper headline
ISSUE: UTF8 characters not supported when drawing to Image

Add Builder project files

They were named so for compatibility with make, but make doesn't use
the anymore. I always forget whether it's SHARED_RAYLIB or
RAYLIB_SHARED...

For now, RAYLIB_SHARED and STATIC_RAYLIB may still be used,
but print a deprecation warning.

Integrate develop branch

Rename: GetHexValue() renamed to ColorToInt()
Added: ColorToHSV()

Integrate develop branch into master

Linux make install improvements

These changes are intended to provide context and control over the Linux make install process. make install RAYLIB_LIBTYPE=SHARED now works as expected. libraylib.so is properly installed with attendant runtime links. The examples will be running against the newly installed libraylib.so unless otherwise specified with RAYLIB_RUNTIME_PATH. See raylib/src/Makefile and raylib/examples/Makefile for usage of RAYLIB_INSTALL_PATH, RAYLIB_H_INSTALL_PATH, and RAYLIB_RUNTIME_PATH variables. RAYLIB_RUNTIME_PATH in particular is interesting for portability since sudo isn't needed.
The default configuration and workflow is essentially unchanged and unaffected.

If user doesn't build the static library,
`pkg-config --static --libs raylib` should be equivalent to
`pkg-config --libs raylib`.

Fixes this build failure:
http://www.cpantesters.org/cpan/report/a069fade-0e1f-11e8-a1cf-bb670eaac09d

- Some functions renamed
- Comments reviewed
- Functions reorganized

Otherwise we may run into LoadDefaultFont and crash in rlLoadTexture
Also moves InitTimer() before InitGraphicsDevice(), to allow it to be
tested even if InitWindow ultimately fails.

InitWindow: return false if no monitor found

Otherwise we run into an assertion failure inside GLFW's glfwGetVideoMode.
Example:
http://www.cpantesters.org/cpan/report/b4ba5894-0bdb-11e8-841e-2c60b04e1d2d

This is related to #456.

Allows loading of shader from text code string directly

Integrate develop branch

Bump version to 1.9.4

While nice to test, this would mean that the tagged release will depend
on GLFW as well… Therefore disable it for now.