a_to_b -> b_from_a in context.py
a_to_b -> b_to_a in maps.py
a_to_b -> b_from_a in paralleltest_localarray.py
a_to_b -> b_from_a in localarray.py
Merge pull request #243 from cowlicks/to-from-switch

Use `X_from_Y` rather than `Y_to_X`.