Added shareable searches

Each search is now saved in the `location.hash` so that it doesn't interfere with the feature Id URLs. Hopefully, you'll like it.

TEST=
http://localhost:8080/features/#>=36
http://localhost:8080/features#owner:kenji
http://localhost:8080/features#proposed
http://localhost:8080/features/5298357018820608#proposed

BUG=#80
![image](https://cloud.githubusercontent.com/assets/634478/3610879/fa4257f4-0d92-11e4-801d-2fec4947be10.png)
Done.