Apple Swift support

Hello, I've implemented initial support for Swift language. Many things are supported at this moment. I will continue development further when I'll have more time. Please consider this pull request. Thanks.
I've moved more to a style of defining these as class methods that return sets, and checking inclusion in a rule block.  There's a nice concise example of that approach in the Groovy lexer.  It tends to be more performant than monster regexes.