Read survey responses
oh.survey_response.read(campaign_urn,
prompt_id_list = "urn:ohmage:special:all", privacy_state = "both",
column_list="urn:ohmage:user:id,urn:ohmage:prompt:response,urn:ohmage:context:timestamp",
output_format = "json-columns", user_list = "urn:ohmage:special:all",
to.data.frame = TRUE, ...)campaign id
comma seperated ist of promt id's
shared or private
ohmage columns
should be json-columns
list of users
if data should be converted to a dataframe
other args passed to ohmage