Code clean-up desperately needed!

[exclusive-and]

Simply put, at time of writing, the GLR code is a big mess. It needs to be cleaned up.

The especially urgent candidates are:

• Hanjiru.Tomita.tomita: Basically all of the code in here should be split up into tidier functions.
• Hanjiru.Tomita.Reduce.pack: Requires general tidying, and also more efficient handling of list splitting/recombination.

Hanjiru.Tomita.Stack also needs a lot of attention. It needs:

• More efficient equality comparisons for stacks.
• Proper documentation.
• Some more convenience functions.

Also, it's probably worth considering a nice monad or two to simplify some of the variable routing that's currently done by hand.

[exclusive-and]

Another idea for tidying up Hanjiru.Tomita.tomita (and other things): separate the conventional (single-stack) LA/LR functions from the GLR (multi-stack) functions.