Search via lunr.js

lunr.js submodule added and integrated in ratchet.

Demo of this and the [PullToRefresh](https://github.com/SimonWaldherr/ratchet/tree/pulltorefresh) Pull Request https://github.com/maker/ratchet/pull/154 improvement: http://simonwaldherr.github.com/ratchet/test/app/index.html