[Tech Debt]: started the CLI work for PR#49

This pull requests includes the very basic work to start end-to-end testing the arithmetic CLI integration

https://github.com/jspm/jspm-cli/issues/49
This might be preference so I'll follow your lead on this. Some reasoning behind my need to extract - I felt this method was doing 3 things before the refactor

1) parsing the cli to understand what operation to perform
2) doing the simplest case bundle
3) doing any type of arithmetic based bundle

let me know how you want to proceed on this -I could smash it all back into 1 big function