Ensure that g.v(1).properties serializes via rexpro.
Merge branch '23', remote-tracking branch 'origin'
Integration test modifications for failing tests based on dependencies.

Removed orientdb as an integration test target since there are transactional failures.  Moved jerse-client to a test scope in the pom.  ignored the tree test in rexpro client tests as there seems to be either a bug in gremlin or an unexpected change to how tree is presented (the graph instance itself is in the root of the tree).
Add enabled option to integration test rexster.xml for tinkergraph.
Show stack trace when logging graph configuration errors.
Merge remote-tracking branch 'origin/23'