Close #20757: return success for skipped pip uninstall

The 3.4rc2 Windows uninstaller would fail if pip had been updated
to a version that didn't match the version installed by ensurepip.
This skip is no longer treated as an error, so an updated pip ends
up being handled like any other pip installed package and is left
alone by the CPython uninstaller.
Close #20568: install unversioned pip command on Windows
Issue #20731: Properly position in source code files even if they
are opened in text mode. Patch by Serhiy Storchaka.
Merge with 3.3
Merge heads
Reindent
Issue #20650: Tweak some awkward wording.
Issue #20778: Fix modulefinder to work with bytecode-only modules.

Bug filed and initial attempt at a patch by Bohuslav Kabrda.
merge for issue #20778