Prepare for packaging

[brbsix]

Here's an outline of the changes:

• Add requirements.txt to MANIFEST.in so that it will be included during packaging. It was previously unable to uninstall in package form.
• Convert README.md to README.rst with pandoc (PyPi only supports reStructedText).

• Force absolute imports everywhere. Was previously seeing the following error in Python 3:

  Traceback (most recent call last):
  File "/home/user/.local/bin/dockerize", line 7, in <module>
    from dockerize.main import main
  File "/home/user/.local/lib/python3.4/site-packages/dockerize/main.py", line 11, in <module>
    from dockerize.dockerize import Dockerize, symlink_options
  File "/home/user/.local/lib/python3.4/site-packages/dockerize/dockerize.py", line 16, in <module>
    from depsolver import DepSolver
  ImportError: No module named 'depsolver'

• Populate setup configuration.
• Use argparse's version action.
• Add usage message to --help.
• Include installation instructions in README.rst.
• Follow PEP8 style guide as much as possible.
• Use semantic versioning (e.g. 0.0.1)

As far as I can tell, it should be ready to upload to PyPi. However I haven't tested it yet as I didn't want to register the package and prevent you from doing so. You'd probably want to upload it to the PyPi test server to ensure everything is functional. Documentation is prone to break if there are any errors in README.rst. Also note that you may want to select a LICENSE.

[larsks]

I've merged most of these changes. PyPi doesn't get to dictate of the format of my README file, though.

[larsks]

Dockerize is now on PyPi: https://pypi.python.org/pypi/dockerize

[brbsix]

Awesome... Also you can edit the PyPi description at https://pypi.python.org/pypi?:action=submit_form&name=dockerize&version=0.2.2 without affecting the .git repo if you care to. I agree though, it's unfortunate Markdown isn't supported (natively).