stub support for specifying a source of templates on the commandline

[wearpants]

This probably needs more work (tests or whatever), and perhaps there's a cleaner approach, but it suits my purposes and didn't eat my lunch. Refs #22.

Adds --template / -t flag to management command to specify a package to use for template source.

[Brobin]

Looks great! Could you fix the little pep8 issue and then update the readme with a description and maybe an example of how to use this?

[auvipy]

awesome

[tigrus]

When it will be pulled? :)

[Brobin]

I'm not sure I like the idea of "copy all of the templates into your package". I think it might make more sense to just fork the project at that point.