Add Clojure support

[sarcilav]

This includes comments recognition and basic metrics.

[adam-waldenberg]

Hi @sarcilav. Looks interesting. We can add it as a default extension, but I would prefer that the support for the metrics is "complete". I really don't kow much about clojure, but looking at it seems the "(" character is also used within if statements and other things.

[sarcilav]

@adam-waldenberg true, the thing is that there is not the concept of if as an statement or reserve word, it is just another function

[adam-waldenberg]

@sarcilav What about the macros covered in;

http://clojure.org/api/cheatsheet

Looks to me like the branch and loop sections under macros might be candidates to add to the regexp in gitinspector. Then again, I'm guessing these are just some macros defined by default and you could potentially do anything you want ?

Maybe the best course of action is to indeed use "(".