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 branch 'master' of github.com:qutip/qutip into feature-supertests
Added stub, unit test for super_tensor.
Extended permute to type='super'.
Moved rand_super out to random_objects.
Continued work on permutation.

Reshuffling now works from superoperators to reshuffled
superoperators, but it fails to be self-inverse. This is, at least,
being caught by the new unit test.
Got reshuffling working. Now for super_tensor.
Finished first version of super_tensor, and unit test works.
Fixed problems with tests, rand_objects.
Changed Qobj into new-style class.
Fixed reshuffle to work w/ Py3k.
Merge pull request #99 from cgranade/feature-supertests

Feature: unit tests to check superrep metadata preservation