Increase code test coverage

[jotterbach]

Current test coverage is fairly low

----------- coverage: platform linux, python 3.6.1-final-0 -----------
Name                                             Stmts   Miss  Cover
--------------------------------------------------------------------
grove/__init__.py                                    1      0   100%
grove/amplification/__init__.py                      0      0   100%
grove/amplification/amplification.py                70      3    96%
grove/amplification/grover.py                       41     41     0%
grove/arbitrary_state/__init__.py                    0      0   100%
grove/arbitrary_state/arbitrary_state.py            95     45    53%
grove/arbitrary_state/unitary_operator.py           42     17    60%
grove/bernstein_vazirani/__init__.py                 0      0   100%
grove/bernstein_vazirani/bernstein_vazirani.py      57     49    14%
grove/deutsch_jozsa/__init__.py                      0      0   100%
grove/deutsch_jozsa/deutsch_jozsa.py                72     62    14%
grove/fermion_transforms/__init__.py                 0      0   100%
grove/fermion_transforms/bktransform.py             38      6    84%
grove/fermion_transforms/fenwick_tree.py            52      0   100%
grove/fermion_transforms/jwtransform.py             24      0   100%
grove/phaseestimation/__init__.py                    0      0   100%
grove/phaseestimation/phase_estimation.py           45     45     0%
grove/pyqaoa/__init__.py                             1      0   100%
grove/pyqaoa/maxcut_qaoa.py                         39      9    77%
grove/pyqaoa/numpartition_qaoa.py                   30     30     0%
grove/pyqaoa/qaoa.py                               113     17    85%
grove/pyqaoa/utils.py                               16      0   100%
grove/pyvqe/__init__.py                              0      0   100%
grove/pyvqe/vqe.py                                 128     30    77%
grove/qft/__init__.py                                0      0   100%
grove/qft/fourier.py                                34      3    91%
grove/simon/__init__.py                              0      0   100%
grove/simon/simon.py                               158    102    35%
grove/teleport/__init__.py                           0      0   100%
grove/teleport/teleportation.py                     27     27     0%
--------------------------------------------------------------------
TOTAL                                             1083    486    55%

@ncrubin @willzeng what are the low hanging fruits and dangerzones. I.e. what should be addressed first?