Update masked array copy to preserve array order

Using 'K' to try to match array order, fixes https://github.com/numpy/numpy/issues/3156
Adding a test for #3265

Test to ensure that MaskedArray.filled() doesn't change the order of the array.

This test is a little messy because there are problems constructing an F-contiguous masked array in the first place. I had to explicitly pass in F-contiguous arrays for data and mask.
Merge pull request #3265 from jamestwebber/patch-2

Update masked array copy to preserve array order