Add matchesRegexString: method (and option version) to NSString category

Useful not to have to use the RX() macro when migrating from RegexkitLite.
Also the 'matches' method is ambiguous, takes NSRegularExpression/NSString depending on type and confuses the compiler when operating on ids. This one is unambiguous.
Add range options to match functions
Add replace & componentsSeparatedBy helpers