raw.github.com links should use raw.githubusercontent.com instead

[JobLeonard]

In order to better isolate your content from potentially malicious content uploaded by other users (e.g., content that might contain Cross-Site Scripting or other embedded attacks), we now serve user-generated content from subdomains of githubusercontent.com. This content is no longer served from subdomains of github.com.

##What's affected?

This change affects the following subdomains:

• raw.github.com : Serves raw file content from your repository.
• embed.github.com : Allows users to embed rich GitHub content on other sites.
• render.github.com : Displays rich content on GitHub.com.
• f.cloud.github.com : Hosts all those amazing gifs you use in Pull Requests and Issues.

Content formerly served by these subdomains is now served from subdomains of githubusercontent.com.

https://developer.github.com/changes/2014-04-25-user-content-security/

For example, revisions.txt (in fact, I don't know if there are any other links to raw.github).

https://raw.github.com/processing/processing/master/build/shared/revisions.txt

https://raw.githubusercontent.com/processing/processing/master/build/shared/revisions.txt

The first link should just redirect to the second, but on my system that doesn't happen, for some reason.

As first raised here: processing/processing#4947 (comment)

[JobLeonard]

Apologies, I've just been told this should go in processing-docs instead