restore use_umfpack option with a deprecation warning, not to break backwards compatibility when it is not necessary
pep8 fixes
use full module name instead of abbreviation
Use qutip.settings.debug flag instead of explicit argument verbose in steadystate module.
Removing timing functions as builtins in qutip.steadystate. Profiling and benchmarking should be done externally.
merge
Added test generator for arithmetic preserving superrep.
Added checking of scalar operations, more verbose output.
Added sub and div.
Adding tensor check revealed problem with superrep and tensor.
Added another test for tensor().
merge
simplify implementation of tensor
add check that all superreps for tensor of super operators are equal.
remove empty line
fixed typos
pep8 fixes
import cleanup
Merge pull request #98 from jrjohansson/steadystate-patches

Steadystate patches
clear isherm flag if False, because we cannot be sure that isherm is False after tensor multiplying nonhermitian opeators (the result could be hermitian)