Generalize 'object_url' to take extra arguments

I used *args so that it would be backwards-compatible with previous usage.
The only difference, and it's minor, is that now all arguments are
urllib-quoted.  Tested with two- and three- argument calls.
Add TODO to fix name of object_url
Merge pull request #145 from gsilvis/cli-generalize-url

Generalize 'object_url' to take extra arguments