Revised autobeam settings patch and ran makelsr.py

Revised autobeam settings patch and ran makelsr.py

Eliminate context properties measureGrouping, beatLength, and
beamSettings

Create new context properties baseMoment, beatStructure, and
beamExceptions.

Save time-signature-specific settings in context property
timeSignatureSettings

Do away with virtually all special rules for beaming; the beat structure
now governs almost all autobeaming.

Fix documentation