Close #12015: The tempfile module now uses a suffix of 8 random characters
instead of 6, to reduce the risk of filename collision. The entropy was reduced
when uppercase letters were removed from the charset used to generate random
characters.
Issue #18405: Improve the entropy of crypt.mksalt().
(Merge 3.3) Issue #18405: Improve the entropy of crypt.mksalt().
Issue #18425: Add docstrings to IdleHistory.py.  Remove redundant 'history_'
prefix from two attributes and two methods of History class.
Merge with 3.3
Issue 18719: Remove a false optimization

Remove an unused early-out test from the critical path for
dict and set lookups.

When the strings already have matching lengths, kinds, and hashes,
there is no additional information gained by checking the first
characters (the probability of a mismatch is already known to
be less than 1 in 2**64).
merge
Issue #8713: Support alternative start methods in multiprocessing on Unix.

See http://hg.python.org/sandbox/sbt#spawn
Remove errant fourth '.' from ellipsis in datetime documentation.