support for node 0.8.x with YuzuJS's setImmediate implementation

[MBThaumatec]

Hi,
This are correction that are needed to support node v0.8 with incomming MQTT.js v1.0.0.

[mcollina]

You can just do a

// setup the global setImmediate if missing
require('setimmediate')

without assigning it to anything.

[MBThaumatec]

I push your suggestion, but I can see there is issue with Travis CI tests. I'm quite sure it's about too old npm version. With node 0.8.x in Travis there is npm v1.2.x. As you can see here:
npm/npm#4984
or
npm/npm#5906

this npm version is not working good with ^ - compatible version mark which you are using in package.json. It should be at least npm v1.4.x.

What we can do about it?

[mcollina]

replace all ^ in package.json with ~, for our purposes it is very similar.

[MBThaumatec]

OK, I'll do. I was thinking that maybe there is way to tell nvm in Travis to use newer version of nvm. But I'm not familiar with Travis, and my searching for such option in travis.yml was not successful. I thought, that maybe something you can do on Travis webpage.

[mcollina]

you can run npm install npm@latest -g as a before_install command. Actually, this is definitely better than the package.json fix.

See http://docs.travis-ci.com/user/build-configuration/#Build-Lifecycle.