Simplify output handling for binary morphology.
Fix overflow in NumPy 1.7 as suggested by Julian Taylor.
Restore @ahojnnes's overflow test.  Correctly assign out argument.
Test that output argument is utilized.
Test that output argument is correct.
Revert to >0 for determining binary values. Document that input should be binary.
Pre-allocate memory for convolution and re-use for output, if no user-override specified.
Allocate less memory, if possible.
Update docs to match output.
Tweak markup of docstring.
Always use uint8 for binary view.
Merge pull request #778 from stefanv/binary_morph_out

Simplify output handling for binary morphology.