Support for multi argument parameters

[DarkArc]

Allow ArgumentConverter to specify a range of arguments for instance, for a coordinate parser, you could specify that 1 - 3 arguments should be tried. The parser can then trial parse 3 arguments, and walk down until it gets a match, or it fails.

[octylFractal]

Personally I am not willing to make this happen soon, but I am not against it. If someone PR's it, then I will review and merge it, but I believe it will require a significant rewrite of the current parser.