Arguments need validation

[viveleroi]

1. Arguments should be validated by type. If I use Argument.forInt().name("r").build(), r:test should return an error to the user.
2. It would be nice to provide a regex/custom validator method. I need to parse a coordinate to x,y,z format.
3. I would also want the ability to customize the message returned to the user. I use localization so it would be nice to have an error interceptor or something.