Avoid using QuTiP 4.4.0 on Travis/Appveyor

All problems introduced in QuTiP 4.4 were worked around, except for
qutip/qutip#1047

A fix to qutip/qutip#1047 was merged into
QuTiP's master, so presumably the problem will disappear with the next
release of QuTiP.

This commit specifically excludes QuTiP 4.4.0 from being installed on
Travis and AppVeyor. We do not exclude that version in the list of
dependencies in setupy.py, because the issue is mostly cosmetic
(although it will fail tests). The average user should be OK using
krotov with QuTiP 4.4.0

Closes #49

.appveyor.yml

@@ -16,7 +16,7 @@ install:
   - echo CONDA_PREFIX %CONDA_PREFIX%
   - echo PATH %PATH%
   - conda config --append channels conda-forge
-  - conda install qutip
+  - conda install qutip>=4.0,!=4.4.0
   - pip install .[dev]
   - pip freeze
 

.travis.yml

@@ -16,7 +16,7 @@ install:
   - conda create -q -n test_env python=$TRAVIS_PYTHON_VERSION
   - conda activate test_env
   - conda config --append channels conda-forge
-  - conda install qutip
+  - conda install qutip>=4.0,!=4.4.0
   # we must use an editable install, otherwise coveralls won't work
   - PIP_USE_PEP517=false pip install -e .[dev]
   - pip install coveralls