Add syntax highlighting

[dwitterer]

This was previously discussed in #247, but it seems that noone has actually gotten round to implementing this. Therefore, I opened a seperate issue for this, well... issue, as per @lionleaf's request (and common sense).

The basic gist:

• The highlighting should be done client-side for performance (obviously :/)
• We can use libraries like highlight.js and syntax.js, so we don't even need to write anything special

Easy stuff to do - we just need to source highlight.js and use it on code blocks, updating on every newCode, but we kinda abandoned the idea, so... here we are again.

[dwitterer]

If anyone does feel like doing something more, however, then a bracket matcher would also be great. This would basically just check if the character behind the caret is a ( or ) and look back for the previous/next matching bracket accordingly. In Atom, for example, it looks like this (you might have to enlarge the image quite a lot - github compression screwed up the image quite badly):

[imscary]

I was going to create this issue too! Syntax Highlighting will make that text area look awesome. Highlight.js is the best here in my opinion.

[joeytwiddle]

#99 also had some suggestions:

• Ace (Ajax.org Cloud9 Editor) https://github.com/ajaxorg/ace/
• CodeMirror https://github.com/codemirror/codemirror (I think codegolf.tk uses this one)
• Highlight.js https://github.com/highlightjs/highlight.js

[MostlyEmre]

Syntax highlighting seems to be added in beta.dwitter.net