Show Teachers -> USA zoom & pins

[thadk]

• "Show teachers" button zooming to USA and displaying all schools as pins from database. Teachers appear in panel when you click on a school pin.

[thadk]

Subtask was to get a JSON object for this. This was partly implemented in 9f300ac

It will be at:
http://peacecorps.herokuapp.com/map/get_schools/

Needs a dict with zipcode->longlat conversion like this one to be added to our data_options file for crossreferencing: https://raw.github.com/davglass/zipcodes/master/lib/codes.js