update readme
Rearrange Dockerfile to improve caching and make most rebuilds superfast
Add "dput" to requirements.txt since Paul forgot it :)
Refactor "bin/crank" with more sanity-checking goodness and more nice, clean output
Add "-nc" to "dpkg-buildpackage"

Closes #1 (for now)
Merge pull request #3 from tianon/refactor-crank-script

Refactor "bin/crank" with more sanity-checking goodness and more nice, clean output