thumbor-9999.ebuild: Update to post v6.0

Bump from 97a5559 (5.2.0~3) to bc49cb3 (6.0.1-131-gbc49cb3).

Drop the Thumbor fork of pexif [1], the unused python-magic
dependency [2], gevent [3], pymongo [4], and pyvows [5,6] (but
not preggy [7]).

I have not included:

* The new argparse dependency [8] because Python 2.7 includes argparse
  [9].
* nose-focus, because the only current nose_focus use in in
  .coveragerc for a 'report' target, and we're only using the 'run'
  target.

Also bump from EAPI 5 to 6 and from git-2 to the newer git-r3 (there
were no changes impacting this ebuild [10]).

[1]: https://github.com/thumbor/thumbor/issues/294
     Subject: As pexif is now on pypi revert from thumbor fork
[2]: https://github.com/thumbor/thumbor/pull/734
     Subject: Remove unused python-magic dependency
     $ git describe --contains origin/pr/734
     6.0.2~10^2
[3]: https://github.com/thumbor/thumbor/pull/735
     Subject: Remove unused gevent dependency
     $ git describe --contains origin/pr/735
     6.0.2~11^2
[4]: https://github.com/thumbor/thumbor/commit/a733977c2d8da5fd6253535b8471c1afb3887a8a
     Subject: removing mongo from setup.py
     $ git describe --contains a733977c
     6.0.0b1~27
[5]: https://github.com/thumbor/thumbor/commit/f4c9e1fc7e77a4b8d5abc432e7afa60f77c816b2
     Subject: Setting tornado 4.1 version
     $ git describe --contains f4c9e1fc
     5.0.0-rc1~4
[6]: https://github.com/thumbor/thumbor/commit/1e985972b8c08d27b289bb306b075194cc960ee5
     Subject: Removed pyvows
     $ git describe --tags 1e985972
     6.0.1-91-g1e98597
[7]: https://github.com/thumbor/thumbor/pull/743
     Subject: Make dependency on preggy explicit
     $ git describe --contains origin/pr/743
     6.0.2~7^2
[8]: https://github.com/thumbor/thumbor/pull/588
     Subject: Feature/nosetests #
     $ git describe --contains origin/pr/588
     6.0.0b1~30^2
[9]: https://docs.python.org/2.7/library/argparse.html
[10]: https://devmanual.gentoo.org/ebuild-writing/eapi/#eapi=6

files/init.d/thumbor: Change the default port to 8888

Avoid:

  Traceback (most recent call last):
    File "/usr/lib/python-exec/python2.7/thumbor", line 9, in <module>
      load_entry_point('thumbor==4.5.4', 'console_scripts', 'thumbor')()
    File "/usr/lib64/python2.7/site-packages/thumbor/server.py", line 87, in main
      server.bind(context.server.port, context.server.ip)
    File "/usr/lib64/python2.7/site-packages/tornado/tcpserver.py", line 162, in bind
      backlog=backlog)
    File "/usr/lib64/python2.7/site-packages/tornado/netutil.py", line 90, in bind_sockets
      sock.bind(sockaddr)
    File "/usr/lib64/python2.7/socket.py", line 224, in meth
      return getattr(self._sock,name)(*args)
  socket.error: [Errno 13] Permission denied

because port 80 is a privledged port, and it's not worth using an
additional service like authbind [1] to give us the capability to bind
to it.  8888 is unprivileged, and it's Thumbor's default [2]

[1]: http://en.wikipedia.org/wiki/Authbind
[2]: https://github.com/thumbor/thumbor/wiki/Running#-p-or---port

files/init.d/thumbor: Remove --syslog option

Thumbor doesn't support syslog-logging out of the box (yet [1]).

[1]: https://github.com/thumbor/thumbor/issues/377

thumbor-9999.ebuild: Hard-code OpenCV Python version

media-libs/opencv uses python-single-r1, which means it doesn't like
our ${PYTHON_USEDEP}:

  emerge: there are no ebuilds built with USE flags to satisfy
  "media-libs/opencv[python_targets_python2_7(-)?,-python_single_target_python2_7(-)]".

Note the '-' in front of python_single_target_python2_7.  I'm not sure
what the best way to handle this is, since *without* the OpenCV
dependency, Thumbor could theoretically be installed for multiple
Python versions simultaneously.  It would be nice to translate the
OpenCV ebuild to python-r1 or distutils-r1, but it ties the Python
binding config into its main CMake setup:

  local mycmakeargs=(
    ...
    $(cmake-utils_use_build python opencv_python)
    ...
  )

That makes it hard to step in and build Python bindings for a
different version.  Until someone thinks up (or tells me about) a
cleaner way to handle this, I'm just going to hardcode the
single-version we need.

dev-python/thumbor: Add this image-thumbnailing service