* Fix keyboard state change detection on RPI

* Rework RaspberryPi evdev keyboard input.

- Extract evdev keyboard handling into PollKeyboardEvents()
- Move keyboard polling to main thread
- Rename EventThreadSpawn() to ConfigureEvdevDevice() as it doesn't necessarily spawn threads
- Remove unused code (KeyEventFifo and lastKeyPressed)

* Replace tabs with 4 spaces.

* Update CMakeOptions.txt

* Update config.h.in

I usually try to avoid any return in the middle of functions, I try to keep them always at the end of the functions.

* Don't create an ortho matrix when the viewport is 0 in any axis.
Not all compilers divide by 0 and return inf, some segfault.
The matrix is not used by anything when minimized, so it just needs to not be called.

* Better fix that always ensures the rlgl matrix is always valid

* Better fix that always ensures the rlgl matrix is always valid

Resolves #1495
This line allocated some memory that was already allocated in the beginning of the function and was essentially creating a leak.

* Don't use DrawRect to clear an image, a pixel loop is an order of magnitude faster.

* Update ImageDrawRectangle to be faster too.

* Added a new utility function to get the current monitor.

Some of the other functions rely on passing on a monitor id but we only have a function for querying the count of monitors available.

* Updated the comment to correctly reflect the function action

This monitor should even probably be passed as an id instead to make it more consistent with the rest of the API but this would break existing applications so I am hesitant to change the function signature directly.

* Add quadratic bezier to shapes.c

* Add DrawLineBezierQuad to header

Removed function from raymath

* Add a function to know if two lines intersect each other and if yes, get the intersection point

* Remove indents

* Rework the declaration of the 'Vector2LineIntersect' function, and add the 'Vector2SegmentIntersect' function

* Remove bad indents

* Fix compilation issues

* Fix compilation error

* Fix compilation error

* Replace keyword '_Bool' by 'bool'

Just for a better consistency

Exposing internal memory allocator/free, useful for advance users when required

Pefixing/Suffixing some data type identifier in the variables is not a convention used in raylib, just reviewed it for consistency...

Still, I kept the *Rec suffix in some functions.

Previous implementation did not consider any padding while drawing the characters on screen (despite being available on the font atlas), so, only minimum character area was drawn.

If some text effect shader was required (shadow, glow, outline...), there was no space in the drawn quad to draw that pixels effect.

This commit corrects that issue.

This is a BREAKING CHANGE!

To address the linked issue, several functions have been renamed and couterpart functions have been created to free loaded memory:
 - RENAMED: GetImageData() -> LoadImageColors()
 - RENAMED: GetImagePalette() -> LoadImagePalette()
 - RENAMED: GetWaveData() -> LoadWaveSamples()
 - ADDED: UnloadImageColors()
 - ADDED: UnloadImagePalette()
 - ADDED: UnloadWaveSamples()

Previous GetKeyPressed() method was actually returning unicode codepoints equivalent values instead of the key-code of the pressed key. So, it has been replaced by GetCharPressed(), returning unicode codepoints and GetKeyPressed() now returns key-codes.