Fixes for leaked connection

 - Also introduces reason in the Disassociate message
 - Reliable delivery now transitions from idle to active if there are pending system msgs
 - Minor fix in merging receive buffers (reduces resends)
 - Tweaked WireFormat
 - Removed busy-wait in startup
 - throwing the proper exception type in EndpointReader
 - InvalidAssociationException extends NoStackTrace
Merge pull request #1552 from drewhk/wip-connection-leak-fix-drewhk

Bugfixes aplenty -- connection leak and reliable delivery fixes