Started moving code from simulator index.js to Game class. Works but is tangled.
hexmap and currentBag moved into Game.
GameBuilder added. Moved tile mixing there.
Global variables mostly eliminated. Input fields still referred straight from game and builder classes.
Removed form value accessors from game and builder. Inherit common property setter method.
Update tile mixes when number of types is changed.
Inherit in javascript prototype style.
Create tilebags in builder. Minor cleanups.