More temperament layouts, automatic color schemas

• Change: Complete rewrite of temperament::EqualTemperament, moved to layout::EqualTemperament
  • New: Add EqualTemperament::get_colors for auto-generated color schemas
  • Improvement: Add EqualTemperament::get_keyboard to obtain an isomorphic keyboard layout
• Change: Merge temperament::{TemperamentType, TemperamentPreference} into a single type layout::PrototypeTemperament
  • Improvement: Add PrototypeTemperament::Mavila9 and PrototypeTemperament::Porcupine8
  • Improvement: TemperamentFinder::{by_edo, by_step_size} now returns a list of matching temperaments
• Change: Move key::Keyboard to layout::IsomorphicKeyboard
  • Change: IsomorphicKeyboard now returns a scale degree instead of a PianoKey
• Change: Move all types of the comma package to temperament
• Improvement: Add Val::pick_alternative to select the second-best prime representation ("wart")