to avoid curses.unget_wch bug present in older versions of ncurses such as
those shipped with OS X.

- Remove OS X installer and Mac/Makefile dependencies on /Developer which
  no longer exists with Xcode 4; the referenced tools have been installed
  into the usr/bin tool root since Xcode 3.
- Support adding the SDK usr/bin tool root to the installer's PATH via the
  SDK_TOOLS_BIN environment variable.

__import__().

To help explain why the -1 default value is typically not seen, a note
about how import statements only use values of >= 0 is also noted.

'u' format of the array module uses again Py_UNICODE type for backward
compatibility with Python 3.2.

The only change from Python 3.2 is that PyUnicode_AsUnicode() result is now
checked for NULL value.

Issue #14814: Remove redundant property from interface objects - prefixlen can be accessed via the associated network object

Issue 14814: Docs work showed some more cases of networks pretending to be addresses and highlighted the weird approach to implementing the 'is_whatever' properties. Impl now illustrates far more clearly that networks have a property if both their network and broadcast addresses have that property

Close #15559: Implementing __index__ creates a nasty interaction with the bytes constructor. At least for 3.3, ipaddress objects must now be explicitly converted with int() and thus can't be passed directly to the hex() builtin.

Patch by Roger Serwy.

Patch by Roger Serwy.

os.sched_setaffinity now use regular sets of integers to represent the
CPUs a process is restricted to.