HQ master

Note this PR is dependent on https://github.com/apache/activemq-6/pull/1 (Please merge this before pushing the commits from this PR).

Applies all commits from the initial ip-clearance zip based on commit 90d43fbc158a0e6e3028c7179dbcf984757b88fb through to last commit of HornetQ master (currently 8ef48cc33d6d61041f4c932085d5c426f789620c).