Initial implementation of integrated hubot.

Script loading isn't quite settled yet; I've only brought over the
`ping` script for now.  The `codex` script will have to be reworked to
use direct `Meteor.call` invocations; there might also be some
`Meteor.bindEnvironment` required (but maybe not).

Hubot has been upgraded from v2.3.4 to v2.10.0.  This brought with
it a few changes to adapter internals.  One of the nice new features
is that hubot supports listening to multiple rooms.  The integrated
hubot is currently listening to *all* chat rooms now.  Hubot scripts
also can distinguish between `hear` (which is all messages, not just
those directed to hubot) and `respond` (which is just messages starting
with `bot` or `codexbot`).  You can also `emote`.  The `ping` script
illustrates the differences.

We might have some "fun" scripts which use `hear` but restrict themselves
to room `general/0`.

We have also added a `priv` response method which returns a private
message to the user.  By default responses to private messages are also
private.

Change-Id: I04c5d7a350bc5bb67a0e561914a5653215ab25b9