DISPATCH-56: Make dispatch management client library public.

The dispatch management client library is now installed as a normal python package
qpid_dispatch.management

- Added management.Entity with read, update, delete operations.
- Added setup.py.in to install python packages to standard site-directory for CMAKE_INSTALL_PREFIX
- Added VERSION.txt with project version, available in cmake as QPID_DISPATCH_VERSION

- Separate proton.Messenger code from client.Node.
- Add CRUD permissions to schema. Fix status return codes for CRUD ops.
- Added DummyEntity to test CRUD, implements all 4 operations.

git-svn-id: https://svn.apache.org/repos/asf/qpid/dispatch/trunk@1623899 13f79535-47bb-0310-9956-ffa450edef68
NO-JIRA: bin/release.sh verifies that the release version matches VERSION.txt in the checkout.

git-svn-id: https://svn.apache.org/repos/asf/qpid/dispatch/trunk@1623900 13f79535-47bb-0310-9956-ffa450edef68