Support nested config templates

[Dan Black]

Current implementation assumes simple text-only key-value pairs

>>> template = {'foo': {'bar': 'baz'}}
>>> Configify.make(template, secret=False)
Enter value for "foo"
(return for default "{'bar': 'baz'}")': 

Set "foo" to "{'bar': 'baz'}" in config.json

[Dan Black]

could use this library https://github.com/bionikspoon/json_config