ENH: DilateABinaryImage uses FlatStructuringElement.

This is the preferred API.

Change-Id: Ia6d5fe3ca9616acdb77093a72f0ed4ab24dde2cd
ENH: Add DilateABinaryImage.py.

Change-Id: Iec62b97dd865d3958b715ed67c3c40f3632ceaa8
Merge "ENH: DilateABinaryImage uses FlatStructuringElement."
Merge "ENH: Add DilateABinaryImage.py."