(beginning-of-python-def-or-class): Renamed to

py-beginning-of-def-or-class, and defaliased for backwards
compatibility.  ME patch to add optional second argument, count.

(end-of-python-def-or-class): Renamed to py-end-of-def-or-class, and
defaliased for backwards compatibility.  ME patch to add optional
second argument, count.