o _fastmath now builds and runs on PY3K
o Changes to setup.py to allow /usr/include for gmp.h
o Changes to setup.py to allow linking fastmath w/ static mpir
  on Windows without warning messages
o Changes to test_DSA/test_RSA to throw an exception if _fastmath
  is present but cannot be imported (due to an issue building
  _fastmath or the shared gmp/mpir libraries not being reachable)
o number.py has the code to flag a failing _fastmath, but that
  code is commented out for a better runtime experience
o Clean up the if for py21compat import - should have been == not is
o Clean up some '== None' occurences, now 'is None' instead

This should allow people to use something like this if they want
backwards-compatibility:

try:
     from Crypto.Random import get_random_bytes
except ImportError:
     try:
         from os import urandom as get_random_bytes
     except ImportError:
         get_random_bytes = open("/dev/urandom", "rb").read

In an attempt to simplify the copyright status of PyCrypto, I'm placing my
code into the public domain, and encouraging other contributors to do the
same.

I have used a public domain dedication that was recommended in a book on FOSS legal
issues[1], followed by the warranty disclaimer boilerplate from the MIT license.

[1] _Intellectual Property and Open Source: A Practical Guide to Protecting
    Code_, a book written by Van Lindberg and published by O'Reilly Media.
    (ISBN 978-0-596-51796-0)

This will avoid the previous situation where scripts like the old "test.py"
get included accidentally in a release.  It also frees us to put additional
build scripts in the top-level directory of the source tree.