Use `(list* x . more)` and `(,x . ,more)` match patterns.

Rather than `(list x more ...)` and `(,x ,more ...)`.

Former are faster, at least for big N.
Scribble sources: Pygmentize non-Racket code blocks. Closes #91

In a Scribble source, you can use a `pygment-code` function provided by
`frog/scribble`:

    @(require frog/scribble)

    @pygment-code[#:lang "js"]{
    function foo() {
      return 7;
    }
Bump to v0.19