core: Validate OnBehalfOfCompID(115) and DeliverToCompId(128)

OnBehalfOfCompID(115) and DeliverToCompID(128) tags are used in some FIX Drop
messaging to indicate the party, whose message was delivered to the third party
receiving drop copy flow.

Configure SBT to run tests written in JUnit. Also, fix broken tests in
RecvAppOrAdminMsgSpec and SendHeartbeatSpec tests. Make JUnit verbose when
running tests under SBT's as the tests take suspiciously long time to complete.

Drop 'isPointToPoint' from 'Message' and 'MessageHeader' as no longer used.

Signed-off-by: Karim Vuorisara <karim.vuorisara@valotrading.com>
Merge pull request #164 from valotrading/improvements/accept-messages-from-a-third-party

Validate OnBehalfOfCompID(115) and DeliverToCompID(128)