Close #17666: Fix reading gzip files with an extra field.
#17657: Show full Tk version in IDLE's about dialog.
Patch by Todd Rovito.
#17648 - convert test_urllib2.py doctests to unittests
#17678: Fix DeprecationWarning in the http/cookiejar.py by changing the usage
of get_origin_req_host() to origin_req_host.

Patch by Wei-Cheng Pan