If press/release events for a mouse button come too fast, then using
`IsMouseButtonReleased()` does not work. This has been noticed when
using a touchpad on Linux when tapping with two fingers two emulate
right mouse button click.

The situation looks like this:

```
BeginDrawing           <-- current==released, previous==released
Pressed                <-- current=pressed
Released               <-- current=released
IsMouseButtonReleased  <-- returns false because current==previous
EndDrawing             <-- previous=released
```

The fix is to update the previous mouse button state in addition to
current mouse button state when `MouseButtonCallback()` is called by
glfw. Now the situation is as follows:

```
BeginDrawing           <-- current==released, previous==released
Pressed                <-- current=pressed, previous=released
Released               <-- current=released, previous=pressed
IsMouseButtonReleased  <-- returns true because current!=previous
EndDrawing             <-- previous=released
```

It seems to work ok on my old Intel HD Graphics card... it should work anywhere else

* fixes for switching full-screen and v-sync

* requireVsync flag

- Renamed GetGlyphIndex() parameter
 - Review DrawTextEx() implementation
 - Review DrawTextRecEx() implementation

* swapped comments, expanded comment for clarity

* revert alignments

* adjusted for consistency

Just simplified code a bit

Actually OpenAL is not used any more, it should be using CoreAudio

Keeping original API

* add api FIFO based character input.

* rename input character functions

* replace tab to space x4 #1012

* Fix camera not working problem at align z direction. #924

* replace tab to space x4

Uses fewer vertexes than using DrawCube() or DrawSphere() for points.  The small line is on analogy to the code for DrawPoint() in shapes.c.

* [rlgl] Create function `rlUpdateMeshAt`

* [rlgl] Update function `rlUpdateMeshAt`

Corrected bug when loading a RenderTexture texture passing NULL data.

* explained a bit more the core_window_letterbox example

* fixed a few 'ups' moments that could lead to mild head pain and time loss

ADDED: CodepointToUtf8()

RENAMED: TextCountCodepoints() -> GetCodepointsCount()

* Initial commit of addition for GLTF materials.. should support loading more than just albedo map.

* Clean up

* fixed seg faults and leaks

* temp don't overwrite defuse colour when rendering

* undid something dumb!

* correctly mixed diffuse map color when rendering to preserve not overwrite it

- Improved LoadBMFont()

Now it accepts a ';' separated list of extensions, useful to check multiple extensions

Get the unicode equivalent characters (as int array) from a UTF-8 text array... maybe this function is renamed to be clearer to users...