Make CoffeeLint a peerDependency

CoffeeLint 1.4 added the ability to the locally installed version of CoffeeLint when run from the command line. It uses the same mechanism as how `grunt-cli` gets globally installed, but runs your project's version of `grunt`. I haven't used `gulp`, so I don't know how it works.

Lets say a user has globally installed CoffeeLint 1.5, but their project using `gulp-coffeelint` is still using 1.4. As a `peerDependency` the user gets the same results (1.4) when run from the CLI (which is usually used by editor plugins) and from `gulp-coffeelint`.