Add warning to OpenURL()

See https://github.com/raysan5/raylib/issues/686

Improve OpenURL()

Calling just `xdg-open` is not right. One needs to pack the URL in `'`.
If we don't do this then some special characters (like ampersand) will
be executed.

Maybe this is true for Windows and Apple case too, but I don't own any
such system. So please merge this, and if it's true for more cases let's
use `sprintf()` in the other cases too.

OpenURL() is a function that most games probably will never need.
Wasting 512 bytes to store of a static char to store an the URL is not
wise.

I propose to have it dynamic building the string on the fly.

Corrected bug on ImageDrawRectangleLines()

REVIEWED: ImageDrawRectangle()
ADDED: ImageDrawRectangleLines()

By default, internal white texture was used to draw most of the shapes; some time ago, support for white font character from default internal font was added. That way, all basic drawing (shapes, text) could be performed without a texture change and in a single drawing pass.

Now, we move a step further and we allow configuring the texture (and rectangle) used to do the shapes drawing.

Wait for input events passively (sleep) instead of polling events actively every frame

- Updated dr_mp3 and implemented it
- Reviewed sampleCount vs frameCount
- Reviewed XM playing (some weird things...)

text:     IsEqualText() -WIP-
audio:  SaveWAV()
audio:  ExportWaveAsCode()
textures:  ExportImageAsCode()

Pathdefines

The comment sais it allows max 256 files, but the MAX_DIRECTORY_FILES
define actually is set to 512.

Let's have a seperate if linux block for this. Since we will need to
define MAX_FILEPATH_LENGTH for all other cases. And its more readable
like this.

On Linux systems the length of the path is defined in linux/limits.h as
PATH_MAX.
Lets use that for MAX_FILEPATH_LENGTH, which is a define that we can
find in some comments in the code that is actually never used. Instead
often we see 256 handwritten.
So lets have MAX_FILEPATH_LENGTH as a proper define, being set to
PATH_MAX on Linux and to 256 on Windows systems.

VSCode Project Updates

Vscode updates

pull

Added RaspberryPi option to ignore duplicate touchscreens (Default on)

Added multitouch example

RaspberryPi Mouse and touch overhaul

Why am I still supporting this???

Update

...disposing RenderTexture.

Remove non-Windows includes from Makefile