Issue #18103: Update README.txt and test_idle to describe and run gui tests.
#18155: Regex-escape delimiter, in case it is a regex special char.

Patch by Vajrasky Kok, with slight modification to the tests by me.
#18038: Use non-deprecated assert names in tests.
Issue 18189: remove unused methods in idlelib.Delegator.Delegator.
Idle code already uses x.delegate instead of x.getdelegate().
The printed report must have been for testing.
Issue #18224: Removed pydoc script from created venv, as it causes problems on Windows and adds no value over and above python -m pydoc ...
Issue #18224: Updated test.