General better support for different types and advanced vol options

[lsolberg]

See discussions in #2

I have a very big and advanced schema containing things like:

{
        Required('triggers', default=defaults): {
            Required('run', default=defaults['run']): bool,
            Optional('time'): All(
                list, Unique(),
                Length(min=1), [
                    validators.Regex(r'^[0-2][0-9][0-5][0-9]$')
                ]
            ),
            Optional('every-x-seconds'): All(
                int, Range(min=5, max=60 * 60 * 24 * 7)
            )
        }
    }

This library didn't like that, so I made some changes, but I'm not sure what the history behind them are..

See comments in PR