Added preference-based dispatching. Looks for the active context with the highest priority with a "http://registry.gpii.org/common/matchMakerType" preference and dispatches to the matchmaker specified there.
Merge remote-tracking branch 'AndreasStiegler/master' into MM-dispatcher
Example of unit test for Andy
Merge pull request #1 from kaspermarkus/MM-dispatcher

Example of unit test for MM dispatcher
GPII-438: Dispatcher tests
GPII-438: Dispatcher tests (bugfix)
GPII-438: Dispatcher sample profiles.
GPII-1044: Merging in MatchMaker dispatcher from Andys repo