Issue #21855: Fixed the decimal module in unicode disabled build.

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branch : 2.7
Issue #22632: replace dead link with version-specific doc link.

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branch : 2.7
Issue #3068: Change 0/1 to False/True so that extension configure dialog can
easily recognize and display boolean values as such and recognize changes.
Also reformat comments and alphabetize extensions included with Idle.

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branch : 2.7