s/path importer/path based finder/ (because the path based finder is not an importer and the simpler 'path finder' is too ambiguous)

Close #14814: Avoid depending on struct by using newer features. Also use enumerate where appropriate (patch by Serhiy Storchaka). Declaring PEP 3144 final at this point - any further changes to code or docs can go in new issues.

Issue #14814: document the Interface APIs and fix various problems with the string representations (initial patch by Eli Bendersky).

Patch by Francisco Martín Brugué.

Patch by Francisco Martín Brugué.

for certain locales (utf-16 and utf-32 family).

Patch by Chris Jerdonek.

for certain locales (utf-16 and utf-32 family).

Patch by Chris Jerdonek.

Patch by Kushal Das.

Patch by Kushal Das.

Patch by Chris Jerdonek.

Patch by Chris Jerdonek.

This is analogous to the link for `flie objects` in the description of
'open' that exists in the 2.7 docs, and adds a similar link to the
io docs.

Patch by Chris Jerdonek.

This is analogous to the link for `flie objects` in the description of
'open' that exists in the 2.7 docs, and adds a similar link to the
io docs.

Patch by Chris Jerdonek.

filling up with random data.

command lines.  It was broken as a side effect of the changes to
pythonw.c in b79d276041a8 for #15307.  Since sys.executable no
longer includes 'Python.app' in the path name, test for a
framework build instead.  This should give the previous behavior
in nearly all cases.  Whether the previous behavior is sensible
is left as an issue for later releases.  IDLE.app behavior was
not affected as it does its own manipulation of sys.executable.

The code for the class itself isn't deprecated for
backwards-compatibility reasons, but the class shouldn't be directly
inherited by anyone anymore as the API is no longer as widely valid as
it used to be.

When the fromlist argument is specified for __import__() and the
attribute doesn't already exist, an import is attempted. If that fails
(e.g. module doesn't exist), the ImportError will now be silenced (for
backwards-compatibility). This *does not* affect
``from ... import ...`` statements.

Thanks to Eric Snow for the patch and Simon Feltman for reporting the
regression.