Chorale: Simplify code. `getRules` now uses `zipWith`.
Chorale: Simplify code: `getRule` now expects arguments lists with one element less.
Chorale: Simplify code: `getRule` and `getRules` now use pattern matching.
Chorale: Simplify code: `getRule` now uses `zipWith`.
Chorale: Simplify code: `getRule` now expectes list of differences.
Chorale: Simplify code: `getRule` now curried and inlined into `getRules`.