Removed site cache clearing in TestCase._fixture_setup

The test suite doesn't seem to suffer from this removal. Tests
should probably take care themselves to clear caches if they
depend on it.
Fixed #19492 - Added a link to the uWSGI/Django tutorial.
Fixes #20162 -- Added a note in the documentation for `static.serve()` about the need for updating the system's map files when incorrect content types are returned. Many thanks to Simon Charette and Claude Paroz for their feedback.
Fixed some markup in formtools docs.
Fixed #20168 - Generalized a PostgreSQL specific database query in the docs.

Thanks Russ for the suggestion.
Fixed #9913 - Clarified User.is_authenticated docs.

Thanks rshea for the draft text.
Fixed #8649 - Documented a caveat about dynamically adjusting formsets.
Fixed #19220 -- Prevented decimals to be displayed in scientific notation

Thanks nebstrebor for the report and antofik for the patch.
Fixed #20167 -- Preserve the traceback of `ImportError`s in `import_by_path`.

Thanks @carljm for the review.
Updated some 'Dive Into Python' links
Fixed #20172 -- Ensured urlize supports IPv4/IPv6 addresses

Thanks Marc Aymerich for the report and the initial patch.
Added more tests for strip_tags utility

Refs #19237.
Fixed getting max_digits for MySQL decimal fields

Refs #5014.
Fixed #5014 -- Guessed max_digits and decimal_places for SQLite

Decimal is treated as float on SQLite, hence inspectdb can only
guess max_digits and decimal_places arguments.
Imported unittest from django.utils in util_tests

Without this, the 'new' assertion methods are not present with
Python 2.6.
Fixed #16737 -- Support non-ascii column names in inspectdb

Thanks moof at metamoof.net for the report.
Fixed #20169 -- Ensured that the WSGI request's path is correctly based on the `SCRIPT_NAME` environment parameter or the `FORCE_SCRIPT_NAME` setting, regardless of whether or not those have a trailing slash. Thanks to bmispelon for the review.
Relaxed time frame check in test_strip_tags
Fixed deprecation warnings introduced by 97774429aeb54df4c09895c07cd1b09e70201f7d.
Fixed #19748 - Documented django.utils.module_loading.import_by_path