Switch to alternative adapter to fix mentions

The current hipchat adapter has trouble picking up the mentions and saving new users correctly. Someone already did the work, I forked it, trimmed it, and prepped it, so here it is :smile: 

Here's the differences (https://github.com/liftopia/hubot-hipchat/compare/fix-roster-updates):
```diff
diff --git a/src/hipchat.coffee b/src/hipchat.coffee
index e4b1890..9c6d490 100644
--- a/src/hipchat.coffee
+++ b/src/hipchat.coffee
@@ -91,9 +91,10 @@ class HipChat extends Adapter
         for user in users
           user.id = @userIdFromJid user.jid
           # userForId will not overwrite an existing user
-          if user.id of @robot.brain.data.users
+          if user.id in @robot.brain.data.users
             delete @robot.brain.data.users[user.id]
           @robot.brain.userForId user.id, user
+          @robot.brain.data.users[user.id]['mention_name'] = user.mention_name
 
       # Fetch user info
       connector.getRoster (err, users, stanza) =>
```