Add support for mutable strings

[revolter]

It would be nice if replacement methods would work on mutable strings too.

[NoPPT]

Can do this?
NSArray* pieces = [@"A dog,cat" split:RX(@"[ ,]")]; // => @[ RxMatch, RxMatch ]

[revolter]

I don't understand. I was referring to something like

NSMutableString *test = [NSMutableString stringWithString:@"test"];

[test replace:RX(@"t") withString:@"X"]; // XesX

[NoPPT]

I'm sorry, I reply to the wrong place