DataSet, second round
- pull request: Carter Charbonneau
    remove optional null fcn args like f=null, coffeescript creates unnecessary
      if (f == null) {f = null;}
- Refactor importColors/Drawing w/ installColors/Drawing works w/ existing image
- Rename: @patches.patches2Bits->@patches.toBits; ditto bits2Patches/fromBits
- Model.reset refactoring; setWorld method for world object
- Animator: reset
- Contexts reset allows new sizes, world
- Patches can be resized, with fractional size, by reset
- Util: new array methods, typed->js array converter
- importing keeps cache for reset/restart optimization