[Patch #1002763] Allow long ints as terminator values; also, treat a terminator of 0 like the empty string or None

__getitem__() and __setitem__().

Simplifies the API, reduces the code size, adds flexibility, and makes
deques work with bisect.bisect(), random.shuffle(), and random.sample().

* Add doctests for the examples in the library reference.
* Add two methods, left() and right(), modeled after deques in C++ STL.
* Apply the new method to asynchat.py.
* Add comparison operators to make deques more substitutable for lists.
* Replace the LookupErrors with IndexErrors to more closely match lists.

When the null string is used as the terminator, it used to be the same
as None, meaning "collect all the data".  In the current code, however, it
falls into an endless loop; this change reverts to the old behavior.

    last Medusa release)

Should be safe as a bugfix candidate, though it's not fixing a bug.

    documentation purposes.  These implementations are the same as the
    ones suggested by Skip in the bug report.

    http://groups.yahoo.com/group/medusa/message/333

It's clear that Medusa should not be checking for an empty buffer
via "buf is ''".  The patch merely changes "is" to "==".  However,
there's a mystery here all the same:  Python attempts to store null
strings uniquely, so it's unclear why "buf is ''" ever returned
false when buf actually was empty.  *Some* string operations produce
non-unique null strings, e.g.

>>> "abc"*0 is "abc"*0
0
>>>

but they're rare, and I don't see any such operations in asynchat.

(How many opre of these will we need? :-( )

got the order backwards in a line (for .find()).

   to find the prefix of strings, thus removing a warning, and simply
   uses straightforward string slicing.

    (SF patch 101447, fixing PR#113704)

comments, docstrings or error messages. I fixed two minor things in
test_winreg.py ("didn't" -> "Didn't" and "Didnt" -> "Didn't").

There is a minor style issue involved: Guido seems to have preferred English
grammar (behaviour, honour) in a couple places. This patch changes that to
American, which is the more prominent style in the source. I prefer English
myself, so if English is preferred, I'd be happy to supply a patch myself ;)

*this* set of patches is Ka-Ping's final sweep:

The attached patches update the standard library so that all modules
have docstrings beginning with one-line summaries.

A new docstring was added to formatter.  The docstring for os.py
was updated to mention nt, os2, ce in addition to posix, dos, mac.

standard Python library.  (Async socket support.)