so that they call `Crypto.SelfTest.st_common.handle_fastmath_import_error`,
thereby eliminiating duplicate code.

```
ext_suffix = get_config_var("EXT_SUFFIX") or get_config_var("SO")
```

because `get_config_var("SO")` returns None in Python 3.4.0a4 because the "SO"
variable is deprecated and "EXT_SUFFIX" is the new way to get this information
(see: http://bugs.python.org/issue19555)

This fixes `TypeError: Can't convert 'NoneType' object to str implicitly`
errors when running the tests on Python 3.4.0a4.

[dlitz@dlitz.net: Re-ordered commits; so don't import S2V yet]
[dlitz@dlitz.net: Included an additional 'import *' change from the following commit:]
    commit 4ec64d8eaaa4965889eb8e3b801fc77aa84e0a4e
    Author: Legrandin <helderijs@gmail.com>
    Date:   Tue Sep 10 07:28:08 2013 +0200

        Removed last references to ApiUsageError

[dlitz@dlitz.net: Removed unrelated whitespace changes]

[dlitz@dlitz.net: Whitespace changes extracted from the author's pull request:]
- [9c13f9c] Rename 'IV' parameter to 'nonce' for AEAD modes.
- [4ec64d8] Removed last references to ApiUsageError
- [ee46922] Removed most 'import *' statements

Under Python 3.2, unhexlify expects to receive a `bytes` object.
Passing it a (unicodr) `str` object causes it to raise the following
exception:

    TypeError: 'str' does not support the buffer interface

The patch contains the following changes:

- Private RSA keys can be imported/exported in encrypted form,
  protected according to PKCS#8 and:

  * PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC.
  * PBKDF2WithHMAC-SHA1AndAES128-CBC
  * PBKDF2WithHMAC-SHA1AndAES192-CBC
  * PBKDF2WithHMAC-SHA1AndAES256-CBC

  In addition to that, it is possible to import keys i the
  following weak formats:

  * pbeWithMD5AndDES-CBC
  * pbeWithSHA1AndRC2-CBC
  * pbeWithMD5AndRC2-CBC
  * pbeWithSHA1AndDES-CBC

- The following new module (and 1 new package) are added:

  * Crypto.Util.Padding for simple padding/unpadding logic
  * Crypto.IO._PBES for PBE-related PKCS#5 logic
  * Crypto.IO.PEM for PEM wrapping/unwrapping
  * Crypto.IO.PKCS8 for PKCS#8 wrapping/unwrapping

- All Object ID (OIDs) are now in dotted form to increase
  readability.

- Add AES support to PEM format (decode only).
  The PEM module can decrypt messages protected with AES-CBC.

- Update RSA import test cases.

- Updated to PKCS8 test cases

The following changes are included:

- Decoding is a much simpler operation. The internal
  logic is based on stream of binary data, and not
  on string indexing anymore. Additionally,
  decoding used to look like this:

     bitmap = DerObject()
     bitmap.decode(input_buffer, True)
     if bitmap.isType('BIT STRING'):
        ... proceed with parsing ...
     else:
        ... error ...

  Whereas now, it is cleaner and more compact:

     bitmap = DerBitString()
     bitmap.decode(input_buffer)

  Any error condition will lead to an exception.

- isType() method has been removed because of the above.
- Added examples and documentation
- Added support IMPLICIT tags
- Added support for negative INTEGERs
- Added DerSetOf ASN.1 class
- DerObjectID can be initialized from the dotted representation of
  the Object ID.
- DerBitString has a new member 'value' to hold the binary
  string. The member 'payload' should not be accessed anymore.
- DerObjectID has a new member 'value' to hold the dotted representation
  of the Object ID string. The member 'payload' should not be accessed
  anymore.
- Added operator += to DER SEQUENCE. Now it is possible to do:

      my_str = DerOctetString(b'ZYZ')
      seq = DerSequence()
      seq += 0
      seq += my_str.encode()
- Update to test cases

The `disable_shortcut` option served as a workaround in case
`__PCT_CTR_SHORTCUT__` leaked through a wrapper object, but I don't
think anyone actually used it, and it was a bad idea to expose it as
part of the public API.

Now that we do strong type checking inside block_template.c, there
shoujld be no need to ever use this option.  It's now a no-op, retained
for backward compatibility only.  It will be removed in some future
version of PyCrypto.

Affects isPrime and getStrongPrime.

See https://github.com/dlitz/pycrypto/pull/23 ("Store result of
rabinMillerTest in an int.") for the bug report.