Adds provider_business_practice_locations table and `node make geocode` task

Hey! 

This is my attempt to add geocoded locations to the BloomAPI. 

For now, it just focuses on gathering the latitude and longitude inside the new `provider_business_practice_locations` table, which uses the `npi` column as primary key. 

I've added an `INSTALL.md` to have more precise installation details (It's based on http://www.bloomapi.com/contribute)

By default, it uses `mapquest` although that could be easily changed to use other services supported by https://npmjs.org/package/node-geocoder

This pull request is based on issue #48 and not complete yet. It should also modify the API search mechanism to allow a user to search using a geographic point and a miles radius. 

Please review the code and let me know if this is what you had in mind.

Thanks!