Implement API endpoint for Tools search.

Similar to the Cookbooks search, this implements the ability to search for Tools
via the API. It is its own endpoint to not affect the Cookbooks
search endpoint.

    GET /api/v1/tools-search?q=QUERY

The start and items parameters can be provided to adjust the results with
pagination.
Merge pull request #755 from opscode/tools_search_api

Implement API endpoint for Tools search.