Added support for Scheduler.Error notification.
Added test TestSchedulerDriverFrameworkRegisteredEvent to test integration of internal http handler, Scheduler.Registered callback.
split scheduler test into unit and integration to avoid super long file.
Added test for ReregisteredFramework and ResourceOffers messages.
test for OfferRescinded event from master.
Added code to test StatusUpdate event handler.
Changed StatusUpdate event test to test StatusUpdate ACK message.
Added test for LostSlave event handler.
Added test for ExecToFrameworkMessage event handler.
Added test for FrameworkError event handler.
Merge pull request #29 from vladimirvivien/pure

Scheduler Event Handler Tests