Adds 141 passing specs to Msf::Module#search_filter.
 * tests exclusion functionality, type: matching, port: matching, app: matching,
   platform: matching, author: matching, text: matching, name: matching, and
   path: matching.
[RM #4790]
Adds specs for different ref types.
Remove inapplicable comment.
Remove unnecessary whitespace.
Land #2121 - add specs for module search filter