rejects builtin types with not defined __new__.

Patch started by Stéphane Wirtel.

It now has slightly better rationale and a less awkward wording in the
explanation.

Inspired by a report of a neither/or conflict by 'animalize' on docs@.

link counting for directories.

Use time.time instead of time.clock.

failure when the test is ran the second time.

The root attribute was set in parent class in setUpClass and then
overridded in child class in tearDownClass.

in range(0, 256).

whitespace is a substring of smallest leading whitespace.
Based on patch by Robert Li.

Clarify message and expected action for beginners.

Patch written by Bernt Røskar Brenna.

with what findCaller() does when running on non-POSIX platforms.

(alternatively: the normcase calls in both places could be eliminated, but that
touches more code and that refactoring hasn't even been done in 3 yet...)

properly to get the filename of its caller from the stack.  This allows it
to work if run in a frozen or embedded environment where the module's
.__file__ attribute does not match its code object's .co_filename.

This same much simpler always correct approach has already been deployed and
used widely in Python 3.4 per the issue referenced above.

when running the test suite.

Patch by Arfrever Frehtes Taifersar Arahesis.

tab in the IDLE Preferences dialog.  Code patch by Mark Roseman.

the other buttons and the new IDLE Dark theme.