Make test and coverage work

See merge request !1

* LICENSE: Add AGPL LICENSE
* Makefile: Use pycodestyle/pydocstyle instead of pep8/pep257
* libravatar.py: Correct some issues detected by pycodestyle/pydocstyle
* tests/federation.py: Random number generator change
  behavior - therefore need to change the exepected result
* requirements.txt: Add reqs to easier install a working env

By default, the DNS module is using udp.  I discovered this because it would
periodically time out on our server -- requests would sometimes take 30s that
would normally take less than 1s.  I'd like to use tcp for our use case in
order to avoid timeouts. However, that alone is not reason enough to ask
everyone else to use tcp.  They may want udp.  It is faster, right?

While playing with this, I found that on average tcp is repeatably faster than
udp for these kinds of requests.

See tcp:

  $ time python -c """
  import DNS
  DNS.DiscoverNameServers()
  [DNS.Request(name='_avatars._tcp.ralph.id.fedoraproject.org', qtype='SRV', protocol='tcp').req() for i in range(128)]
  """
  python -c   0.10s user 0.03s system 10% cpu 1.270 total

Versus udp:

  $ time python -c """
  import DNS
  DNS.DiscoverNameServers()
  [DNS.Request(name='_avatars._tcp.ralph.id.fedoraproject.org', qtype='SRV', protocol='udp').req() for i in range(128)]
  """
  python -c   0.24s user 0.11s system 3% cpu 9.514 total


Which makes it a more suitable default for libravatar.py, no?

To make sure that we don't introduce a problem similar to the one that
was in the main Libravatar codebase:

  https://bugs.launchpad.net/libravatar/+bug/1363804

Thanks to Ralph Bean for the patch!

http://nedbatchelder.com/code/coverage/