Add R package raylibr as a new binding for the R language

Moved to own repo: https://github.com/raylib-extras/rmem

Tested with latest emscripten 3.1.18

This file requires manual maintenance and continuous review, it also changes from day to day moving sponsors from present-to-past and sometimes the other way round.

GitHub already lists the sponsors on the user profile, in a better an more visual way.

I also have doubts this should be a document distributed with raylib sources...

This PR fixes a bug when music.looping is set to false but the music continues looping.
Also using proper functions to seek to start of an audio file.
Removed old comment.

ISSUE: Front buffer and backbuffer have different clear colors, if no `ClearBackground()` is called by user, there is screen flickering on buffers swap.

It's up to the user to call `ClearBackground()` if desired