Fixes issue 829951 - http://bugs.python.org/issue829951

compliance with PEP 3118.

to work with the newest Sphinx.

are used in a Structure or Union constructor.

passed to a Structure or Union constructor.

that array types do not live longer than needed.

Not sure if these are the correct values, but save_stdout has to be set before its usage...

Refactor if/elif chain for clarity and speed.  Remove dependency on subclasses having to implement _empty and _full.

exec call and when creating a recursive instance.

The duplication is intentional -- this paragraph is in a section
describing additions to the sys module, and there's a later section
that mentions the switch.  I think most people scan the what's-new and
don't read it in detail, so a bit of duplication is OK.

precision. This has been discussed at http://bugs.python.org/issue1682. It's
useful primarily for teaching, but it also demonstrates how to implement a
member of the numeric tower, including fallbacks for mixed-mode arithmetic.

I expect to write a couple more patches in this area:
 * Rational.from_decimal()
 * Rational.trim/approximate() (maybe with different names)
 * Maybe remove the parentheses from Rational.__str__()
 * Maybe rename one of the Rational classes
 * Maybe make Rational('3/2') work.

empty() and full().

Orignal patch (without tests) by Leif Walsh.

Fix 1698398:  Zipfile.printdir() crashed because the format string expected a tuple object of length six instead of a time.struct_time object.

Now that I've learnt about structseq objects I felt like converting sys.float_info to a structseq. It's
readonly and help(sys.float_info) explains the attributes nicely.