Reviewed for PLATFORM_ANDROID and PLATFORM_UWP

Allow use of main instead of android_main

Add orthographic 3d rendering mode

This is already the order that is used for Android. It doesn't appear to
make a difference on desktop but on web using the timer before it's been
initialized (by glfwInit, inside InitGraphicsDevice) causes the a long
(and variable but often several seconds) sleep between the first and
second frame.

Fixes: 468309d ("Early-exit InitWindow if InitGraphicsDevice fails")

Changes motivated by commentary in pull request 513

Changes made based on commentary in pull request 513

Fix an infinite loop in ALSA backend of mini_al.

...PLATFORM_ANDROID on Windows, using MinGW-w64 (x86) provided Make (GCC
7.2)

Fix a buffer overflow in the OSS/BSD backend of mini_al.

Inspired by #504.
Instead of requiring the user to do PLATFORM_ANDROID #ifdefery,
have the android_main entry point exported by raylib and call
the user-defined main. This way many games could (in theory)
run unmodified on Android and elsewhere.

This is untested!

raymath.h: Use C99 inline semantics

Add memory sanitizer for better debug

[fork/master] Fixed some memory leaks and add null checks for consistency

- SetWindowSize() to scale Windows in runtime
- SetMouseScale() to scale mouse input, useful when rendering game to a
RenderTexture2D that will be scaled to Window size (used on rFXGen tool)

GLFW has been updated to latest version, probably this code is not
required any more due to already been integrated into library... but it
needs to be tested...

Renamed function for consistency with a possible Mesh manipulation functions (maybe added in a future). Naming follows Image*() manipulation functions.