All full-text search for org name

Previously, you had to supply the exact organization name to get a match when searching with the "org_name" parameter. Now you can find organizations by only specifying some of the words in the name.

If multiple words are submitted, the search will use an `AND` to find results that match all words. So, given 2 org names, "Peninsula Family Service" and "Peninsula Volunteers", "api/search?org_name=peninsula service" will only return locations that belong to "Peninsula Family Service".
Merge pull request #160 from codeforamerica/full-text-search-for-org-name

Add full-text search for org name