Update future.utils.six to version 1.5.2
Fix construction of newbytes from frozensets
Update What's New page with info about bytes taking frozensets

Also move summary of minor changes to lower section ("Summary of all changes")
Improve docs on import hooks
Docs: Use explicit list calling convention with autotranslate arg
Update whatsnew for upcoming 0.11.3; add scrub_sys_modules()

The new scrub_sys_modules() function in future.standard_library is called by
remove_hooks() and the hooks cm's __exit__ function.
Fix load_module
Update version to 0.11.3 for coming maint release
Improve whatsnew page for v0.11.3
Update standard_library imports in tests
Fix imports in test_standard_library
Quieter test discovery
Add fn to scrub modules from sys.modules that would interfere with importing future.standard_library modules
Fix test_bytes_within_range
Clean up logging in standard_library
Remove an old xfail marker in test_decorators.py
Improvements to the sys.modules scrub functions
Remove old disabled bytes test script
Simplify scrub_py2_stdlib_modules()
Clean up tests

* And remove the libfuturize/test_scripts dir that isn't currently used