Move from backport-util-concurrent to java.util.concurrent and upgrade to ActiveMQ 5.2

• Patch Submitted:

  Yes

I've modified Lingo 1.3 so that it now depends on ActiveMQ 5.2.0 (could not find binaries for the incubator version it used to depend on) and JDK 1.5 removing the use of backport util concurrent in favor of java.util.concurrent. The unit tests currently pass and I have tested the changes in our own app (Atlassian Bamboo).