message: conv.setTimeout(timeout) method documented.
diff: @@ -887,6 +887,8 @@ so that it is sent immediately, before any other queued messages.
  `convo.next()` proceed to the next message in the conversation. *This must be called* at the end of each handler.
  +`convo.setTimeout(timeout)` times out conversation if no response from user after specified time period (in milliseconds).
  +
  ### Handling End of Conversation
  Conversations trigger events during the course of their life. Currently,
  