Port many graph introspection features from osrf fork

[ivanpauno]

Continues https://github.com/ros2-java/ros2_java/pull/220. Ports:

• osrf#25
• https://github.com/osrf/ros2_java/pull/32
• https://github.com/osrf/ros2_java/pull/26
• https://github.com/osrf/ros2_java/pull/31
• https://github.com/osrf/ros2_java/pull/38
• https://github.com/osrf/ros2_java/pull/27
• https://github.com/osrf/ros2_java/pull/33
• https://github.com/osrf/ros2_java/pull/61
• https://github.com/osrf/ros2_java/pull/90

[ivanpauno]

@jacobperron this is ready for review now

[ivanpauno]

@jacobperron friendly ping