Parsed Pluperfect

[billroper]

I had just about finished rearranging the parser logic in Java, when I realized that I could substantially improve my life by adding a helper class that keeps track of the current bit of the string that's being parsed, the position of that string relative to the original string (for error messaging), and the operator to apply to the bit of string once the parsing is complete.

So I'm refactoring. The resulting code will be much easier to live with and quite likely much easier to convert to some "standard" parsing system in the future, if that proves to be helpful.