test_functools hanging on the Android armv7 qemu emulator.

This makes tests passing after changes by issue #5322.

Improve speed of dict literal with constant keys up to 30%.

Original patch by Andreas Stührk.

writes the index file when it is not changed.

writes the index file when it is not changed.

Prepare for 3.6.1.  Any further 3.6.0 release candidates and 3.6.0 final will be cherrypicked and merged here.

Patch by Serhiy Storchaka.

again.  But they still are deprecated and will be disabled in 3.7.

The fix for catch_warnings() is the issue #28835 (not the issue #28089).

Issue #28089: Fix a regression introduced in warnings.catch_warnings(): call
warnings.showwarning() if it was overriden inside the context manager.

Handling zero-argument super() in __init_subclass__ and
__set_name__ involved moving __class__ initialisation to
type.__new__. This requires cooperation from custom
metaclasses to ensure that the new __classcell__ entry
is passed along appropriately.

The initial implementation of that change resulted in abruptly
broken zero-argument super() support in metaclasses that didn't
adhere to the new requirements (such as Django's metaclass for
Model definitions).

The updated approach adopted here instead emits a deprecation
warning for those cases, and makes them work the same way they
did in Python 3.5.

This patch also improves the related class machinery documentation
to cover these details and to include more reader-friendly
cross-references and index entries.