Update nforce and add bluebird to package.json

[trevorscott]

Hi, Thanks for this super simple demo app.

When i was setting it up I got stuck on an error:

"400::The replayId for channel {/topic/mypushtopic} wasn't found using the " +
'provided replay ID map {{}}. Ensure that the channel name you provided in ' +
'the replay map is valid and matches the channel name used for subscribing.'"

After googling i found this thread about the issue:

kevinohara80/nforce#178

I was able to fix it by using the streaming-2.0 branch of nforce:

"nforce": "github:kevinohara80/nforce#streaming-2.0"

Also, after making this update to the package.json file I also needed to include the bluebird dep in the package.json as well.