Separate CLI into its own file

[appsforartists]

I was getting syntax errors from Webpack because you start index.js with a hashbang. I broke out the core functionality into its own file to ameliorate this. The logic is all the same.

[dominictarr]

this is a bug in webpack not in this module. there are many node modules that have #! at the top, I recommend putting a pull request into webpack instead.

[appsforartists]

Be that as it may, separating out the concerns of the module itself from those of the CLI is still a net gain.

Even if you disagree with the motivation, is there any harm in accepting the patch?

[dominictarr]

merging this would leave a bug in webpack, though. Not fixing that would be a far greater tragedy than my not merging this. ;)

[dominictarr]

p.s. this works in browserify, there is no reason it shouldn't be supported in webpack.
all that is needed is a regular expression that removes the #!...