BF: fix to Newman Partition to not split partition if eigenvectors are all positive or all negative, clean up docs
BF: add catch in Newman Partition for partition with 1 or fewer edges
RF: changed rule to check for eig vectors all of the same sign in Newman Partition
TST: added tests for newman_parition  function, added ValueError if graph passed has weighted matrix
Merge pull request #9 from cindeem/fix_newman

Fix newman_partion from creating empty partitions