SS updates

- Set use_rcm=False by default and use COLAMD ordering by default.

- Fixed bug in power method.
check for integer input in maximally mixed state
force input to be int

conforms to the input criteria for maximally mixed state
merged Paul's PR 95
use 1d arrays instead of 2d array of shape [N, 1] for rhs in solving linear system (the sparse solver requires this)