Update for Tracer project
- DataSets
  - add toContext, convert toImage to use it
  - toPatchColors/toDrawing: add rest of image args, defaulted
  - toPatchVar: if length is patchs length, don't sample
  - added convolution utilities for: dzdx, dzdy, laplace8, laplace4
  - PatchDataSet: add arrayType for typed array usage
  - ImageDataSet: use util imageToData* procs
- AgentSet
  - own(vars): vars can be array of strings or string w/ spaces
  - add generalized floodfill
- AgentSets
  - Patches: use setCtxSmoothing utility
  - Patches: add floodfill override with p.n as neighbor function
  - Patch: add patchAt dx, dy
- Model
  - @div: now is html element, rather than element id string
- Util
  - add tls (toLocaleString) .. good for comma-readable numbers
  - add firstOneOf in array
  - uniq: no-op if a.length<2
  - aMax, aMin, aSum: convert from "reduce" to work with typed arrays
  - add image data methods:
    cloneImage, imageToData, imageRowsToData, pixelBytesToInt, pixelByte
  - imageToCtx: update to scale image if width,height given
  - ctxToImage replaced by ctxToDataUrl and ctxToDataUrlImage
  - removed unused canvasToImage, canvasToImageData, imageToCanvas, copyCtx
- Models
  - HTML title now model's name
- Cakefile
  - add git diffs for source and models