QPIDJMS-15: implement the asymmetric unsigned byte/short methods

git-svn-id: https://svn.apache.org/repos/asf/qpid/jms/trunk@1576835 13f79535-47bb-0310-9956-ffa450edef68
QPIDJMS-15: ensure we always throw the required IOOBE's, those raised as side effects of the method natural implementation dont account for some corner cases

git-svn-id: https://svn.apache.org/repos/asf/qpid/jms/trunk@1576836 13f79535-47bb-0310-9956-ffa450edef68