Fix upstream issue #62, handle expired keys.

 * see https://code.google.com/p/python-gnupg/issues/detail?id=62
Merge branch 'release/1.0.1'
Merge branch 'master' into develop
Add a 'generated-keys' subdirectory to gnupg.GPG.homedir.

 * Add GPG._generated_keys as an _utils.InheritableProperty class for storing
   a configurable (even by subclasses of GPGBase, without property overrides)
   subdirectory of whichever directory gnupg.GPG.homedir is set to. This
   subdirectory can be used via the 'separate_keyring=True' option to
   gnupg.GPG.gen_key_input(), which will switch temporarily to new pubring.gpg
   and secring.gpg keyrings during key creation, and upon finishing creation
   of the new key, will ask for the new key's fingerprint, and move the
   keyrings into this GPG._generated_keys directory, renamed in the format
   "<GPG.homedir>/<GPG._generated_keys>/<fingerprint>.[pub|sec]ring.gpg".
Change _copy_data() error handling to explain errors not due to broken pipes.
Fix a misnamed variable in gnupg.py; self._key_dir→self._keys_dir
Remove commented out code from GPG.gen_key() for import after generation.

 * Generated keys in separate keyring would not be available after switching
   back to the normal keyrings (not the ones set up for key generation), so at
   first in the unittests I imported them back into the main keyrings… this,
   however, is would be stupid, as in nullifies half the reasons for using
   separate keyrings in the first place, thus the code was commented out. Now
   that the temporary keyrings are placed in the gnupg.GPG._generated_keys
   directory, it would be nice to eventually either extend GPG.import_keys()
   or add a new helper function for doing:

       $ gpg --no-default-keyring --keyring pubring.gpg \
            --keyring ./generated-keys/<some_fingerprint>.gpg
Set gpg.temp_[key|sec]ring to None after setting key.[key|sec]ring.

 * Change the returned _parsers.GenKey from gnupg.GPG.gen_key() to store the
   location of the renamed temporary keyrings as attributes. This way, one can
   do something like:

   >>> key = gpg.gen_key(key_input)
   >>> key.keyring
   './generated-keys/328A5C6C1B2F0891125ECBE4624276B5A2296478.pubring.gpg'
Change setup.py to rename the package from 'python-gnupg' to 'gnupg'.

 * To import, the same 'import gnupg; gpg=gnupg.GPG' is still used, so this
   changes nothing for applications which have started using this fork.

 * This name appears to be untaken on PyPI, the changes I've made thus far are
   significant, and, I believe, are not entirely backwards compatible with
   upstream, do to various keyword argument and method renamings and such.

 * Upstream is unresponsive, their development is private, and the only way to
   get their code is to download an entire tarball and do a diff, since no
   public CVS is available. Also, looking at their recent releases in the past
   five months, they appear to be fixing bugs I've already fixed, albeit in
   different ways -- and not all of the bugs I've fixed, as the shell escape
   trick still works in upstream's 0.3.4 version -- which leads me to believe
   that they are generally oblivious to this fork, though I have tried to
   contact them several times.

 * At first, I merely bumped the major version number up to indicate the
   incompatibility, but in order to upload to PyPI it would need a different
   name, and so I might as well pick a new one and just go with it, in order
   to avoid the general confusion which might result from keeping the name
   'python-gnupg'.
Change the _generated_keys directory for unittests to be under tests/files/.
Change unittest for separate keyrings to add extra --keyring option for now.

 * At some point, as mentioned in an earlier commit, we should actually make
   some sort of helper function for adding extra keyring, so that their keys
   can be used/imported/exported/whatever the user wants to do with them,
   without changing the normal main keyrings.
Move tests/* → gnupg/test/*
Add test logs and files to gitignore.
Add repoze.sphinx to docs dependency 'extras_require' setting in setup.py.
Merge branch 'develop' into feature/module-layout