updated decomp.py for python3, mostly getting rid of xrange and cast returns of map, filter, set to lists; commiting a py2 copy for reference; main command line tools seem to work in py3

added command line utility to verify that CheckDecomposition output looks ok; could have caught previous bugs, looks ok now

fixed bug in enumeratePencils which kept some valid pencils from being printed; other functions correctly identified when valid pencils were present so only bug at last step of printing

moving newer FFT decomposition python code to its own package, module, namespace, whatever; will add command line wrappers and README