Boolean operation error

[vafaei-ar]

Dear developers;

I found out that there is an inconsistency between your package and newer version of numpy, so I've correct it as below way:

sum_threshold.py: line 189:

dilated_mask = binary_mask_dilation(dilated_mask - mask, **di_kwargs)

    dilated_mask = binary_mask_dilation(np.logical_xor(dilated_mask, mask), **di_kwargs)

[jakeret]

Sweet. Could you send me a Pull Request that I can merge into the codebase?

[vafaei-ar]

It's done.