Make _to_own_unit aware of dtype of value coming in
Also ensure NaN are treated properly; add test cases
Speed up check if dtypes same; ensure numpy 1.5 does not fail
Changelog entry that quantity objects can be assigned NaN
Merge pull request #2695 from mhvk/quantity-do-not-prevent-recarray

Bug in Quantity.itemset for NaN values
Ensure in-place ops on Angles with non-angle result do not corrupt the instance
Add __numpy_ufunc__, adjust tests, remove numpy-dev bugs (closes #2483, #2492)
Add numpy 1.9.0b1 to travis tests
Get Angles to work as well: __numpy_ufunc__ for Latitude, Longitude
Hack for earth.py to work around segfault due to numpy bug with recarrays
Add _check_unit and _check_can_cast to reduce code duplication