Patch by Stefan Krah.

Analysis by Victor Stinner. Patch by Stefan Krah.

Patch from Taihyun Hwang.

Patch by Roger Serwy.

Patch by Roger Serwy.

Issue #14814: reorganize ipaddress documentation and document all attributes of IPv[46]Address objects

Issue #15425: Don't rely on the assumption that the current working directory is on sys.path (this will hopefully appease the XP buildbots)

Close #15486: Simplify the mechanism used to remove importlib frames from tracebacks when they just introduce irrelevant noise

faulthandler requires the importlib if "-X faulthandler" option is present on
the command line, so initialize faulthandler after importlib.

Add also an unit test.

'level' values and set its document default value to 0.

Thanks to Arfrever Frehtes Taifersar Arahesis for filing the bug.

those which now have additional XXX's here.  I'll get to those later. :)

Followup to issue #15489.

instead of 100, to be able to display long file paths

the Apple-supplied Tck/Tk versions shipped with OS X 10.7 and 10.8.
They are not as buggy as the 10.6 version but can still easily crash.

Also add tests in the OS X installer build to ensure that the desired
dynamic linking with an optional newer Tcl/Tk in /Library actually
happens.

Patch by Serhiy Storchaka.