Add Quick Look plugins

[gamtiq]

Put "Add ____" as Title [X] Done

Provide a link to the proposed addition. https://github.com/sindresorhus/quick-look-plugins

Explain why it should be added Currently QuickLook Plugins section contains the only item. The proposed set represents useful plugins for QuickLook.

Additional context Plugins are useful for developers.

Issue Checklist

Put an x in the boxes once you've completed each step. You can also fill these out after creating the issue. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before responding to the issue.

• [X] I have checked for other similar issues
• [X] I have explained why this change is important
• [X] I have added necessary documentation (if appropriate)

[alichtman]

• http://www.quicklookplugins.com/

(Merged from #640)

[ThomasWaldmann]

close?