Improve UI and interaction

[KinanBab]

• Alternative Node.js/command line interface
• Double check memoization
• Macros for manually specializing carousels static type parameters in input code
• Interactive and gradual "hole parameter" substitution with verbose symbolic expressions by user
• Interactive and gradual "hole parameter" substitution with advice (e.g. take max) by user
• Plotting several functions (relative to the same or different costs and languages) together for comparison
• Recover 3D plot capability form old UI

[KinanBab]

UI now uses mathjs's simplify operation, this does not simplify simple recurrences or iffs..