Issue #19232: Speed up decimal import.  Additionally, since _decimal is
self-contained, this change facilitates maintenance and the Python version
can be easily imported for experimentation.

--HG--
rename : Lib/decimal.py => Lib/_pydecimal.py
Whitespace.
Issue #22369: Change "context manager protocol" to "context management protocol".

--HG--
branch : 3.4
Issue #22369: Change "context manager protocol" to "context management protocol".
y2k compliance, lol (closes #22380)

--HG--
branch : 3.4
merge 3.4 (#22380)
Issue #22338: Fix a crash in the json module on memory allocation failure.

--HG--
branch : 3.4
(Merge 3.4) Issue #22338: Fix a crash in the json module on memory allocation
failure.