Code generator for Julia

Hi @athurston,

I've written a code generator for the Julia language for ragel 7, which I'm using in a project. It passes all tests, and has been working very well for me.

The code generated requires julia 0.3 which will be released soon (I lobbied to get goto statements added to the language recently, specifically because I wanted to generate fast ragel parsers), and also requires a small [Switch.jl](https://github.com/dcjones/Switch.jl) package that adds a switch statements to the language.

It would be great to have this merged, but I'm OK maintaining a fork if you'd rather not add more languages at this point.