src/ui.js: Allow 2nd line for parameter name, replace pop size with depth.
src/{ui,game,constants}.js: Start system of global parameters with defaults.
src/{ui,game,constants}.js: Formalize parameters into a global constant.
src/constants.js: Reformat PARAMS, add types.
src/{ui,game}.js: Read parameters from input boxes on new game.
src/game.js: Add logic to determine number of reads from depth.
src/co{nsta,mpone}nts.js: Put all popup elements on same Z plane.