Make it easy to geocode cities for the map

1. The new process: Add each city to the `data/locations.yml` file.
2. Run `rake locations`. This will generate an appropriate
`public/data/locations.json` file
Add locations from Google Spreadsheet
Update with the feedback from @coreyhaines
Merge branch 'maintainable_locations' of https://github.com/graysonwright/GDCR into graysonwright-maintainable_locations

Conflicts:
	Gemfile
	Gemfile.lock
Switches from using .rvmrc to .ruby-version

RVM prefers using .ruby-version these days

This commit also upgrades Ruby 2.1.2, which the gemfile states is now
required.
Reorders entries in the Gemfile.lock file
Styling clean slate, use Bourbon & Neat for layout

See:
http://bourbon.io/
http://neat.bourbon.io/