Forced build-time dep on ngmin

Basically, because `angular-socket-io` depends on `ngmin` for proper minification, using the development version to generate minified bundles oneself without using `ngmin` (e.g. the standard usage of RequireJS optimizer) will mess up the deps annotation. Surely one could disable the minification in requirejs, `ngmin` the requirejs output and subsequently minify, but it seems to be a little inconvenient. While `ngmin` is an awesome tool overall as described, it may or may not be desirable or usable for all. So what's the recommended solution to this? Documenting this caveat in README would help. I realize that you're the author of both libraries and certainly have pride in both; hence I'm not requesting removal of the dep but just documentation. Hell I'm just going to integrate `ngmin` into my (affected) project, and who I am to decide for your project!

Thanks a lot!