use node namespace for topics and services
use the node name in the service discovery call
Merge pull request #11 from osrf/issue_11

Use private namespace for services and topics
Move tracebacks of service calls to debug logging
Merge pull request #14 from osrf/issue_14

Avoid tracebacks for "expected" errors?
Merge branch 'master' of https://github.com/osrf/capabilities into bit-pirate