Backport gvanrossum's checkin of revision 1.9:

There's no need for typechecks on the second and third argument of
new.instancemethod() -- the instancemethod object is now a perfectly
general container.

This fixes SF bug ##503091 (Pedro Rodriquez): new.instancemethod fails
for new classes

This is a 2.2.1 candidate.

parameter may be omitted or None.

<lannert@lannert.rz.uni-duesseldorf.de>.

versions.  XXX comments only need to be grep-able.

Edited several of the descriptions for English usage and more
consistent style.