Quick post: Add Phantomjs with Behat.

#163 
@amitaibu Javascript tests are working after installing PhantomJs.
Testing is done with: ``bin/behat -p phantomjs``

The test:
![selection_039](https://cloud.githubusercontent.com/assets/7369740/4884860/bcd98314-636f-11e4-9368-94bd878f3745.png)


The node ceated by PhantomJs:
![selection_040](https://cloud.githubusercontent.com/assets/7369740/4884870/d4982bae-636f-11e4-9dd1-c8f234fe1e64.png)