documentation review fixes
Add TM Locator impl to JMSBridge tests
Allow tests to set TM in TMLocatorImpl

Some tests require a proper TM to be returned by the TMLocator
implementation whilst others require a DummyTM to be returned.  This
patch makes allows TM returned by the locator class to be changed by the
test.
Only Set TM on Bridge in QoS modes that require it

The bridge currently tries to assign a TM even when the quality of
service level is set to Duplicates OK.  This QoS does not use or require
a TM.  This patch stops the bridge from attempting to assign a TM for
this QoS and also checks that a TM is set of the other QoS.  If TM is
not set for a QoS that requires one, a error is logged and RunTime
exception thrown.
Set TM as loaded only after a TM is located.

Previously the ServiceUtils component responsible for loading the
transaction manager would attempt to load a TM only once.  If it was not
found it would not try again.  This patch updates the ServiceUtils to
iterate over any TransactionManagerLocator implementations on the class
path and check each one util a TM is located.
Merging #46 on TM Fixes
Merging #45 on doc changes (review fixes from Andy)
ACTIVEMQ6-61 SelectorParser package conflict with openwire tests

The SelectorParser class in amq6 source code conflicts
with the same class in activemq 5 client jar. The activemq 5
client jar is needed to run openwire tests where the activemq5
client interacts with amq6 broker. In tests they are usually
in the same VM, so depending on the classpath order, whichever
class is loaded it will be used by both client and broker.
Unfortunately the method parse() in the class has different
return types in the client jar and broker side jar.
That will cause NoSuchMethod exception.

The fix moves the broker side class into a different package, i.e.
from
org.apache.activemq.selector.SelectorParser
to
org.apache.activemq.selector.impl.SelectorParser