NO-JIRA: Proton system tests

* Added first simple java system test working for both stacks.
* Added factory to create proton objects (located via ServiceLoader).
* Added factory impl to both stacks.
* Removed JNI_LIBRARIES from swig_link_libraries command.  This was giving unwanted dependencies on libjawt, libmawt.so etc
* Used set_target_properties in bindings/java to work around difference in behaviour between cmake 2.6 and 2.8 re. lib prefix on .so's.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/branches/jni-binding@1428936 13f79535-47bb-0310-9956-ffa450edef68