add versioning with versioneer

[talumbau]

Adding support for versioneer a nice way of doing versioning. The installed package will be able to report its version, which will be useful for reporting results in the webapp.

[MattHJensen]

nice!

[talumbau]

merging so I can attempt a test release.

[MattHJensen]

@hdoupe, is versioneer.py still used for reporting versions on the webapp?

cc @martinholmer

[hdoupe]

No, the version is hard-coded. However, this is not a good solution. I sometimes forget to update the version. Something like versioneer.py would be nice to have for the webapp. This was last discussed in ospc-org/ospc.org#622 (comment)

[MattHJensen]

@hdoupe, sorry I wasn't very clear. What I meant was, does the webapp need Tax-Calculator to have versioneer.py. Otherwise @martinholmer and I would like to delete this file. Is it ok for me to delete versioneer.py from Tax-Calculator?

[hdoupe]

Ohh, I see. Nope, the webapp doesn't require that Tax-Calculator have versioneer, but Tax-Calculator should report it's version in some way that can be accessed programmatically.

[martinholmer]

@MattHJensen and @hdoupe,
After working some on PR #2087, it is now clear that versioneer.py (and some other files I don't understand) are necessary for the repository. So, now I know what's necessary and what's not, but several of the necessary files are mysteries to me.