add node get and post request methods
add node get and post request methods

they replace assign_agent_to_participant, create_agent_trigger and
newcomer_arrival_trigger

jcpeterson/Dallinger,jcpeterson/Dallinger,Dallinger/Dallinger,Dallinger/Dallinger,jcpeterson/Dallinger,berkeley-cocosci/Wallace,suchow/Wallace,jcpeterson/Dallinger,berkeley-cocosci/Wallace,suchow/Wallace,Dallinger/Dallinger,Dallinger/Dallinger,jcpeterson/Dallinger,berkeley-cocosci/Wallace,Dallinger/Dallinger,suchow/Wallace