Added light_plant to the framework

  - Added light_plant.h to blocks
  - Added cmd_led.h to messages.  Controllers should publish
  cmd_led.h to set the light plant.
several changes

  - Changed State namespace to Led_state in order to be more
  specific.  This required multiple changes throughout the
  clearinghouse.h file to use the new namespace declaration.
cleaned up messages and bumper_plant.h