Added a thumbs system

This PR adds to Nerdz an anonymous vote system for posts, implemented as a backend exension and few simple JS additions.
Every user is able to give a +1/-1 vote to any profile/project post with a simple, unintrusive but elegant solution completely integrated with nerdz UI.

![thumbs](https://f.cloud.github.com/assets/424549/2489254/302143ee-b159-11e3-8731-10377c476124.png)

Testing has been done on Windows/Linux (IE/FF/Chrome), but please check locally before putting this into production.

I've also added support to nerdz black. (watch out for a pr)
Template devs should patch their themes if interested with this feature.

Setup:
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1. Execute "setup/add_thumbs.sql". 
2. Pull tpl/0
3. Ready to go!