Make raylib/raygui work better on touchscreen

[casavaca]

Hi,

I'm trying raylib on my iPad using emscripten. I found that raylib and raygui don't work well. We need updated mouse position yet it's never updated (always 0,0). As a result, Cubic-bezier lines doesn't work on iPad.

I don't fully understand how it works on desktop browser, but it may be reasonable to update mouse position of we are using touch screen?

This is not pretty, but after this fix, raylib and raygui work just fine.
If you have better fix, then it's great. Just kindly discard this pull request.

[ghost]

As a result, Cubic-bezier lines doesn't work on iPad.

I don't think all examples were designed with the touch API in mind, which has its own set of functions (L1191-L1196, L1201-L1208) and its own handling.

but it may be reasonable to update mouse position of we are using touch screen?

That assumes mouse and touch should be integrated, which may or may not be the case.

That being said, I think this PR is ok and probably shouldn't cause any major issues. Touches will override mouse position, but any mouse movement will fix that if it happens.

Edit: These comments (R1639-R1641) are probably unnecessary. Also, please mind the coding conventions.

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Footnote: just beware that, right now, mouse input and touch input are different things, so YMMV. When I rewrote the input code for my kernel, I've integrated both in a single API, but it required a considerable architectural change. Mouse and touch require very different handling and making both work interchangeably reliably is complicated.

[casavaca]

I see. I've updated the comments.

[casavaca]

Bump

[raysan5]

@casavaca Thanks for the review. Checking the code it shouldn't be a problem to just map it... let's see...