Dangling transaction handling for B2B MSGSNT
Introduced a better interface to the transaction/request maps.
onB2BMSGSNT erased transaction from wrong cache.
Added error logging.
The global BrokerSettings objects says what's wrong, not only throw.
Removed unnecessary benchmark code
Moved env_vars to root and annotated the variables.
Message relay and remote brokers need to know the sender's user name
Message relay and remote brokers need to know the sender's user name

Conflicts:
	doc/protocols/message-broker-message-relay.mkd
Added sender field for B2B and message-relay protocols
Added DELCHAN-DELTDCHAN command for message-relay
Merge branches 'webapp' and 'mesg-broker'
Some important bugfixes for webapp

...but it runs now, including interaction with message broker and
deeper!