Update the batman.js build process

Time to shed snockets and cake for something more modern. 

I'm moving batman.js code into modules and using node.js requires. So far I've got `karma-commonjs` for running tests. I plan to investigate webpack & browerify for building modules into a browser-friendly file.

I'd love any suggestions or advice or questions regarding this process! I'm new to it but it's gotta be done.