Added the ability to use a like operator with one or more values.
Added not_like operator as the inverse of the new like operator
Added tests for build_filtering_clause to cover the like and not_like operators
Correct OR to AND ( d'oh, that's what I get for rushing! )
Added some documentation around operators, how to use them, and which ones are currently available
Merge pull request #13 from brethir/bv/retrieve_list_like_operator

Added the ability to use a like operator with one or more values.