Upload mesh data to GPU and get VAO/VBO identifiers

As described in the official documentation https://cmake.org/cmake/help/v3.0/variable/BUILD_SHARED_LIBS.html this flag is global by default and controls if the library will be built as a shared or a static library allowing us to define only one call to the add_library function (without specifying its type). It is also added as an option to be visible in CMake GUI applications.

* Better ignore support for idea projects.

Added a wildcard at the end because different configurations would have a diffeerent build directory.

* Removed external from being a relative include directory for target raylib.

Fixes #1533

Corrected bug!

* Delete emscripten.cmake

This file is not needed at this point. EMSDK provides a toolchain file that has a lot more things in it and is better supported. Project currently works fine with the documentation provided in Emscripten SDK on how to build projects.

* First pass file separation.

The main two files are cleaner now. Only important things can be seen. Major changes include:
- raylib_static is now the alias instead of raylib
- Repeating segments are removed and pulled into separate files into <root>/cmake
- File is reordered to make more sense
- Installs are better structured
- Library is build into an output directory "raylib" instead of "src"
- All public header files are now set as a public header file
- Source files need to be listed (it is a bad practice to capture them using wildcards and file globs)
- CMakeLists are better commented

* Second pass on the example dirs.

They are quite complex so I'm more hesitant to do major changes. Also it works pretty well. Noticed that I forgot one of the seperated files and added it into src/CMakeLists.txt.

* Returned the header copy as it was convenient to have the public headers copied.

* A better description to the variable RAYLIB_IS_MAIN

Co-authored-by: Rob Loach <robloach@gmail.com>

* Remove debug message

Co-authored-by: Rob Loach <robloach@gmail.com>

* Improvements based on review.

* Simplify the install condition to not be platform specific as it was before.

Co-authored-by: Alexander Neumann <30894796+Neumann-A@users.noreply.github.com>

* Remove some CMAKE variables as they don't affect the build in any way

Co-authored-by: Alexander Neumann <30894796+Neumann-A@users.noreply.github.com>

Co-authored-by: Rob Loach <robloach@gmail.com>
Co-authored-by: Alexander Neumann <30894796+Neumann-A@users.noreply.github.com>

Now it compresses/decompresses valid DEFLATE streams instead of zlib streams. It uses the minimal and efficient libraries: sdefl/sinfl.

* 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