def set_email(email, vars = {}, lists = {}, templates = {}, options = {})
      data = options
      data[:email] = email
      data[:vars] = vars unless vars.empty?
      data[:lists] = lists unless lists.empty?
      data[:templates] = templates unless templates.empty?
      api_post(:email, data)
    end
def set_email(email, vars = {}, lists = {}, templates = {}, options = {})
      data = options
      data[:email] = email
      data[:vars] = vars unless vars.empty?
      data[:lists] = lists unless lists.empty?
      data[:templates] = templates unless templates.empty?
      api_post(:email, data)
    end
params:
   email, String
   vars, Hash
   lists, Hash mapping list name => 1 for subscribed, 0 for unsubscribed
   options, Hash mapping optional parameters
 returns:
   Hash, response data from server

 Set replacement vars and/or list subscriptions for an email address.