SCV-24: Drop the BlobMaker factory class and integrate the logic it implements into the find function for the Blob class
SCV-24: consolidates the blob's "moments" from individual "m##" properties to a "moments" hash which uses 00,01,10,11 etc
SCV-24: clean up Blob library
SCV-11: Move shannon/plugins/fastener/contour.py into SimpleCV
SCV-24: clean up Blob library
SCV-25: refactor of DrawingLayers to separate out pygame into its own renderer
SCV-26: create SVG renderer, make default for ipython notebook
SCV-27: add an openCV renderer for DrawingLayer, make default for internal use eg in blob.isCircle
SCV-28 make pygame an optional module