Completed FriendGateway, necessary tests and abstract Gateway
FriendGateway and Gateway no longer use a RecordSet. They now use
ResultSet instead (java.sql.ResultSet) and a special case of ResultSet
(NullSet) to denote a lack of results.
Removed RecordSet and updated dependent classes
Merge remote-tracking branch 'origin/master'

Conflicts:
	swe400fitness/src/recordSet/RecordSet.java