Diagrams for the scorer.

First pass at some logical diagrams for how the scorer will work.
1. Parse the xml document.
2. Filter the xml down to relevant musical elements.
3. Obtain difficulty policy (could be from code, config files, or database).
4. Apply policy to the given input to determine weights.
5. Sum up information and output final score.

This omits the logic for multiple policies for the player's level. However, that addition would simply be a difference in how to select the policy.