Introducing version.py and using it in setup.py to get the python

package version number from `git describe`, so we can have officially
tagged versions, and releases distinguished by commit hash.

Also introducing Makefile, which helps regiment some of these setup.py
commands, and will facilitate auto testing.

I have tested this with pypi by creating:

https://pypi.python.org/pypi?%3Aaction=pkg_edit&name=pyaccumulo-dev

and verifying that this works in a setup.py of a project depending on this package:

    install_requires=[
        'pyaccumulo_dev >= 1.5.0-SNAPSHOT.1',
    ],

Problem:  a pull request like this does not transmit tags.  This scheme still works even without tags agreeing across forks, because it constructs release number and uses git hash.  This schemes works better if we coordinate tags by designing a release process that tags versions of this python package with tags like 1.5.0-SNAPSHOT.1   etc.