QPID-5250: Raise all exceptions within Ruby bindings.

Created a static definition for MessagingError in Ruby, then had all
thrown exceptions within the bindings extend that to maintain backwards
compatibility.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1535795 13f79535-47bb-0310-9956-ffa450edef68
NO-JIRA: Fix hanging test test_discards_limit_overflow.

The test was hanging while closing a connection, added a timeout.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1535801 13f79535-47bb-0310-9956-ffa450edef68
QPID-4287: Poor performance when a priority queue with a ring queue policy has a large backlog

LossyQueue::checkDepth was performing an unintended linear search of its
messages when a new message was added at capacity.  Since the messages are in
priority order, only the tail message on the queue needs to be compared with the
new message to determine which of them should be dropped.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1535803 13f79535-47bb-0310-9956-ffa450edef68
QPID-5250: Fixed the ordering of caught/throw Ruby exceptions.

The previous ordering let parent classes be caught before descendant
classes.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1535837 13f79535-47bb-0310-9956-ffa450edef68
NO-JIRA: Correct pkg-config example vars

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1535853 13f79535-47bb-0310-9956-ffa450edef68