Tweak SlackRawMessage to only copy own properties
Tweak SlackRawMessage to only copy own properties

SlackRawMessage copies its properties from the slack-client Message
object. It should only be copying own properties, though, or it ends up
with functions that Message defines (which it turns out are enumerable).

bufferapp/bufferbot-slack,voodoologic/hubot_slack,stackriot/octobot,justjohnpark/gammas-hubot-slack