Some tweaks on BeginVrDrawing()

Two functions have been renamed for coherence; previous naming was confusing for several users:

 - DrawPolyEx()         ---> DrawTriangleFan()
 - DrawPolyExLines() ---> DrawLineStrip()

Basically, formating review and some variables naming to follow raylib conventions.

* Working build

* Fix build again, stop deleting files

* Hotfix crash, needs investigating

* Remove VS2015.UWP, I cannot update the project

* Lots of UWP work, added keyboard and mouse press support. Still need to finish scroll wheel, mouse position and cursor hiding, plus other stuff that I haven't seen yet.

* Implemented a ton more things, added BaseApp.h to provide common code to UWP apps.

* Remove constant window dimensions

* Enable and Disable cursor support.

* Actually use mouse delta

* Gamepad Support

* Cleaning and small tweaks

* Restore original example.

* Update comment

* Use 'Messages' to handle the cursor functions so code is more portable.

* Comment

* Comment unused message fields and use vector for mouse pos instead.

* Move messages to utils.h and use messages for everything. No more plat-specific code in raylib.h

* Working build

* Fix build again, stop deleting files

* Hotfix crash, needs investigating

* Remove VS2015.UWP, I cannot update the project

* Lots of UWP work, added keyboard and mouse press support. Still need to finish scroll wheel, mouse position and cursor hiding, plus other stuff that I haven't seen yet.

* Implemented a ton more things, added BaseApp.h to provide common code to UWP apps.

* Remove constant window dimensions

* Enable and Disable cursor support.

* Actually use mouse delta

* Gamepad Support

* Cleaning and small tweaks

* Restore original example.

* Update comment

* Use 'Messages' to handle the cursor functions so code is more portable.

* Comment

* Comment unused message fields and use vector for mouse pos instead.

* Move messages to utils.h and use messages for everything. No more plat-specific code in raylib.h

* Tested some desktop stuff and added projection matrix updates for window resizing.

* Fixed big bad mouse bug

* Fix alt buttons and add hack to combat flickery key presses (far from perfect)

* Remove debug code

* Final commit

* Well, so I thought

* Wow, i am bad

* Remove packages folder

* Remove useless include

* Apply requested changes and fix linux build

* Try to stop packages folder

* Have we fixed the formatting properly?

* Third time's the charm?

* Where did this come from?

* Re-fix

* Autoformat is gonna kill

* Fixed XBOX ONE Support

* Fix tabs

Trying to define a global transformation matrix to scale all content for HiDPI.

Probably required for HiDPI support

This module still requires further work but 3rd person camera is less broken now...

Found some issues when building for web using latest emscripten 1.38.30, traced the error and found that eglGetProcAdress does not return function pointers for VAO functionality, supported by extension.

It requires more investigation but now it works (avoiding VAO usage)

Users can define their custom memory management macros.

NOTE: Most external libraries support custom macros in the same way, raylib should redefine those macros to raylib ones, to unify custom memory loading. That redefinition is only implemented as example for stb_image.h in [textures] module.

Move to own header for a more deep review of the module

Added experimental network module

At least until a proper solution is found!

Removed a useless semicolon.

This needs to be tested on a hi-DPI monitor, probably requiring a FLAG to enable it would be a good idea...

- No default VR device parameteres inside raylib
- VR device parameter should be provided by user
- VR distortion shader should be provided by user