Close to v1.0 ... extensive changes

  - added get_ptr(int) to Clearinghouse in order to get access to
the pointer in the messages vector from a message id
  - added some todos to Clearinghouse as well
  - added publish_by_id to Publisher
  - added update_by_id to Subscriber
  - completed functioning example of a whisker and bumper controller
with danger close suppport
  - added gw_bare_minimum template to /examples
  - added multi-bumper example to highlight how to construct
multiple nodes that subscribe to the same message type