* Update SPONSORS.md

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* Update CONTRIBUTING.md

* Update CONTRIBUTING.md

Found by grepping for '(blob|tree)/develop'.  See #443 for more information.

* `Alien::raylib` downloads raylib, builds it and installs it in the Perl module path (Basically abusing CPAN as package manager)
* `Graphics::Raylib::XS` depends on `Alien::raylib` and reexports all C symbols as XS symbols usable in Perl
* `Graphics::Raylib` depends on `Graphics::Raylib::XS` and is the actual Perl wrapper with a Perlish API, which users should be using