Call quantize with the following params:
- cell: a square that defines the region that will be quantized (x0, y0, x1, y1)
- inputPixels: a 2d array of rgb-tuples
- outputImage: a PIL image with dims = cell
- thresh: the threshold for sum-of-squares deviations inside of cells
- minCellDims: array where 0: minWidth, 1: minHeight. Smaller cells are ignored (default: 2, 2)
- showEdges: bool, indicates wether cell edges are drawn
- edgeType: if showEdges==true, determines the type of edges. Options: 'black' (default), 'white', 'inv', 'darken', 'lighten')
