Add autocompletion plugin for meteor command

Hi,

I just wrote a simple autocompletion plugin for [Meteor](http://meteor.com).
Here is how it looks like:
![screen shot 2013-09-01 at 6 35 04 pm](https://f.cloud.github.com/assets/1178099/1064317/8546432a-1324-11e3-8396-be34ec8588c8.png)


It's my first plugin so I would be glad to hear if I did something wrong :)

Thank you !