Merge pull request #1623 from AddictedCS/hotfix-reading-nullable-string

HornetQTextMessage sets payload as SimpleString
HORNETQ-1344 StompProtocolManager never cleans up destinations member

Conflicts:

	tests/byteman-tests/pom.xml
https://issues.jboss.org/browse/HORNETQ-1345 - refactor all cluster communications to its own channel
Merge pull request #1627 from gaohoward/master_HORNETQ-1344

HORNETQ-1344 StompProtocolManager never cleans up destinations member
Merge pull request #1628 from andytaylor/master

https://issues.jboss.org/browse/HORNETQ-1345
Upgrade Netty to 4.0.19.Final because of many performance improvements.

The are mostly done in the PooledByteBufAllocator.
Merge pull request #1630 from normanmaurer/netty_upgrade

Upgrade Netty to 4.0.19.Final because of many performance improvements.
hapolicy stuff