Support arbitrary literals in URL dispatch

[cgay]

It isn't currently possible to use URLs that have literal path elements AFTER path variables. There's no reason this shouldn't work and in fact code-browser uses it.

I think a good way to implement this is to parse the URL into path elements and instead of saving just the part before the first path variable, save the entire path with the variable elements marked in some way. To match, all literal elements must match.

I'm not looking at the code, but this seems like it should be a trivial extension.