Debugging/refactoring for NNMC project
- Model:
  - move style: position:relative into ctor
  - start: now waits for modelReady; thus removed setupAndGo, not needed
  - add @drawing.clear()
  - reset: remove black fill of patches ctx
  - ctor:
    - defaults for all parameters other than "div"
    - default isTaurus changed from true to false
    - contexts: add default text parameters tp each context
  - remove label params (moved to agentsets, label, labelColor, labelOffset)
  - remove text params (use util.ctxTextParams)
  - remove setRootVars, replace with debug(@debugging = true)
  - draw: add "force", defaulted to anim.stopped.  Forces draw to occur.
- DataSet:
  - add setSampler: (@useNearest), ctor defaults useNearest to false
  - toImage: add normalize flag and alpha default to toImage()
  - coordSample & patchSample methods added
  - convolve: add factor parameter
  - slopeAndAspect moved from AscDataSet to DataSet, useful for ImageDataSets and others
  - toString: (fixed = false, p=2) -> toString: (p=2, sep=", ") p<0: don't format.
- util:
  - clone: add begin/end for creating subset of array
  - add aProp(array,prop): return an array of a property values of an object array
  - histOf defaults added: bin=1, f=(i)->i
  - add lerp2: (x0, y0, x1, y1, scale) for 2D linear interpolation
  - createCtx: store ctx in newly created canvas
  - ctxDrawText: add "setIdentity=true" argument for push/pop of identity transform
  - remove aMod
- AgentSet:
  - own: simplify interface as a string of names, no defaults
  - remove getProps, setProps
- AgentSets:
  - patches.importDrawing, use => fat arrow
  - remove agents.setDefaultSprite
  - add labels to agents/links, add labelColor, labelOffset properties
  - remove setDefaultXXX val, use setDefault xxx, val instead
  - add patchXYtoPixelXY to complement pixelXYtoPatchXY