Fix typo in comment re modelSetupComplete

IS [#55581994]
D'oh. Simplify references to model.properties
Add custom start/stop/reset/new run to pendulum

IS [#55581994]
Make models playable only if not playing.
Toggle start/stop button enabled state in Pendulum

IS [#55581994]
lint fix
Add experimental 'hasPlayed' output to md2d models
Disable "setup new run" until model has played

IS [#55581994]