hgrecco/pint — pull request #94 by jturner314 (2014-01-28 03:44:17+00:00)
Title: Make normal add/sub use normal, not in-place, ops

In some cases, normal and in-place operations can give different
results. Now, when an operation is done on a Quantity, the exactly
corresponding operation is done on its magnitude, instead of always
using the in-place operation.