Merge branch 'master' into identities-3d-actually-this-time

.gitlab-ci.yml

.test-conda-env-py3-requirements.txt

.test-conda-env-py3.yml

doc/qbx.rst

examples/cahn-hilliard.py

examples/qbx-tangential-deriv-jump.py

pytential/__init__.py

pytential/muller.py

pytential/qbx/__init__.py

pytential/qbx/fmm.py

pytential/qbx/geometry.py

pytential/qbx/refinement.py

pytential/qbx/target_assoc.py

pytential/qbx/utils.py

pytential/symbolic/mappers.py

pytential/symbolic/matrix.py

pytential/symbolic/pde/cahn_hilliard.py

pytential/symbolic/primitives.py

requirements.txt

test/test_global_qbx.py