ENH: Make handle_data overwritable by subclasses.
Merge pull request #1416 from jseabold/handle-data-subclass

ENH: Make handle_data overwritable by subclasses.
TST: NormExpan sandbox.distributions: add basic unittests
BUG: NormExpan sandbox.distributions, no shape parameter see #1397
REF/DOC: sandbox.distribution.extras move examples to script file
DOC/REF: make example script runnable (fix imports)