require Python 2.6
add utilities submodule
replace dictionary generator syntax with 2.6-compliant syntax
fix typo introduced in last commit
make test Python 2.6 compliant
test on Python 2.6
print out Python version to check
include workaround for partial-multiprocessing bug in Python 2.6
test stoichiometric rank computed with new numpy-free SVD
print out Python and NetworkX version
lower networkx requirement to 1.0.1 and higher