Production push: crop popularity, crop suggest, harvest improvements, wrangler improvements, bootstrap 3, and more

New features/improvements:

- crop suggest widget (instead of big dropdown)
- show most popular crops on browse page
- record harvest in ounces
- list of crop wranglers on the crop wrangler page
- edit scientific names on a crop's edit page (crop wrangler feature) 

Bugfixes:

- fixed contact page broken link
- fix harvest "ping" bug

Other:

- upgrade to Bootstrap 3.2
- improve test coverage