Issue #19481: print() of string subclass instance in IDLE no more hangs.
Issue #19928: Implemented a test for repr() of cell objects.
Issue #19407: add Python Packaging User Guide notes

The stdlib docs for package distribution and building extensions
are rather dated, and that isn't expected to change for 2.7 and
3.3.

The Python Packaging User Guide isn't complete either, but it's
already a much better road map for new users than the existing
stdlib docs.
#19943: fix typo noticed by Jakub Wilk.