[issue1682] Move Demo/classes/Rat.py to Lib/rational.py and fix it up.

[Raymond Hettinger]

Raymond Hettinger added the comment:

Were the new methods part of the spec update?  If so that's great.  If
not, we need to take them out.  We want zero API creep that isn't
mandated by the spec (no playing fast and loose with this module).

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