Implementation

As per Myle's suggestion in #28, here's a shitty implementation.md.

@supertopher, I figure you could talk more about why `libexec` is so dope, since it's your baby. If not, I can jump in and write it up and you can proofread? Regardless, I'd appreciate a proofread of what I have so far. I feel like some could be taken out, but I'm not sure. Anyway, have at it.