Tool editing

:hammer: :wrench: Tool owners and Supermarket admins can now edit tools. If the current user has permission to do so they will see a edit button on the tool partial which will direct them to the edit tool form. This also styles up server side validations so they're not quite as ugly as they were.

![screen shot 2014-07-17 at 4 02 04 pm](https://cloud.githubusercontent.com/assets/316507/3618768/4b2e5a50-0ded-11e4-81b5-1e1535863496.png)