Imports of urlshortener command

PathSynopsis
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
github.com/docopt/docopt-goPackage docopt parses command-line arguments based on a help message.
github.com/googleapis/gnostic/plugins/gnostic-go-generator/examples/googleauth
github.com/googleapis/gnostic/plugins/gnostic-go-generator/examples/v3.0/urlshortener/urlshortener
logPackage log implements a simple logging package.