Merge pull request #16 from tmmurali/mohammed

Added tests for node.py
Skeleton for random walk functions and new branch
Incidence matrix function and remaining skeleton for random walk
Updated rest of files that didn't commit
Working transition matrix P for random walk
Documentation and checking matrix invertible
reverted to old graph for testing
Pip8 compliance issues
pep8 stuff
still pep8
last pep8
fixed attribute error
python 3 and 2 usage
python 3 syntax
python 3 is hard
Merge pull request #21 from tmmurali/antuan-tyler

Antuan: Merging directed hypergraph transition/incidence matrices for random walk functionality