Added tests around keyword searching
Added tests around keyword searching

- Testing only for core functionality
	- Single term (i.e. email - anything with email)
	- Multiple terms ANDed (i.e. email support - anything with email AND support)
	- Phrase (i.e. exact "email support" - anything that has the exact phrase "email support")
 	- Negated terms (i.e. email -support - anything that has email and NOT support)

these are all features of the Lucene query string parser which is now enabled.
tests are NOT trying to ensure we support all features of lucent
tests are ensuring the most common (phrase, AND, negate) search uses are support successfully.
- most common is derived from search terms in the analytics

alphagov/digitalmarketplace-search-api,alphagov/digitalmarketplace-search-api,RichardKnop/digitalmarketplace-search-api,RichardKnop/digitalmarketplace-search-api,RichardKnop/digitalmarketplace-search-api,RichardKnop/digitalmarketplace-search-api