Spreadsheet prototype

Hai @audreyt. You should've already got the spreadsheet invite.
This is the idea, roughly (search is not done yet):

![image](https://cloud.githubusercontent.com/assets/1153134/2748250/43da7de4-c7b4-11e3-81c3-e9335d01d4b2.png)

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![image](https://cloud.githubusercontent.com/assets/1153134/2748251/503ab842-c7b4-11e3-9187-daaf196a7e6c.png)