multiple changes

  - Modified Direction to take three letter enums so the control vector
list is easier to read
  - Modified Bump_state so that it can represent three values
  - Added Danger_close_state and supporting functions
  - Changed Scan_pt to include set methods for heading and range
  - Changed Trip_pt to include a third value for a bit flag
  - Modified the bumper example to show the three states for that
Bump_state can be in.
  - WB_controller_example includes the way forward for this next phase
of the project.
  - Cmd_velocity_msg changed to allow construction of fully specified
message.