Bring the CodeMirror (http://codemirror.net/) features to PasteBin (http://pastebin.com/)
More informations here (french) : http://blog.epoc.fr/2013/09/01/codemirror-for-pastebin/
For the (no yet finished) Chrome extension : https://github.com/cGuille/codemirror-pastebin-chrome