NPM Readiness, Lightweight Readme, etc

Hey Dmitry,

Just started having a look at dr.js and also integrating it into my JS build tool [Interleave](https://github.com/DamonOehlman/interleave).  The doctor is great and I definitely think I'm going to use it for quite a few projects.

I notice that you have published eve into NPM so I think there is definitely an opportunity to do the same with the doctor.  I've added the necessary package.json and also a binary wrapper so people will get a dr-js command line executable if they install the package.  I'm not sure you will be comfortable with adding a dependency on [commander](https://github.com/visionmedia/commander.js) but I've found it pretty useful when writing node.js command line tools.

Additionally, I've added a README which I'll happily keep adding to as I find the time and get more familiar dr.js.

Finally, I made a few modifications to the main dr.js file so integration with both the binary wrapper and interleave were a little more seamless.  I'm sure the code is far from perfect, but I think it may help with dr.js adoption.

Thanks again for taking the time to write dr.js :)

Cheers,
Damon.