Refactored some static final to static const
Refactored some static final to static const

brason/three.dart,hirosuke999/three.dart,brason/three.dart,james-storey/three.dart,threeDart/three.dart,hirosuke999/three.dart,brason/three.dart,hirosuke999/three.dart,threeDart/three.dart,james-storey/three.dart,threeDart/three.dart