Merge commit '058ef52c' into demos-added

.gitignore

setup.cfg

src/empyre/fields/field.py

src/empyre/io/field_plugins/vtk.py

src/empyre/utils/misc.py

src/empyre/utils/quaternion.py

tests/conftest.py

tests/fields/test_fielddata.py

tests/fields/test_rotate.py

tests/test_fields/test_field.py

tests/utils.py