Bump pip version about galgebra

[hugohadfield]

@utensil no worries, I think there is not a big rush! I have also been absolutely smothered in work and so have failed to get involved in this. I think I ended up pushing some of those versions into pypi just because I didn't know what I was doing with distribution... I think going to 0.4.3 makes sense

[hugohadfield]

Wrt the pull request I think the work looks fantastic and the docs also look awesome.

[hugohadfield]

@utensil I seem to have managed to get the pypi deployment to work just about with my credentials
https://pypi.org/manage/project/galgebra/releases/

[utensil]

I'm ok with bumping pip version as is but I also would like to include some work in #9 to be merged first.

My work on #9 wasn't solely on documentation but also fixes a series of issues. The PR doesn't have much progress since last Sep due to my busy work and also because I hit a wall that I could not fix the problems I found ( a few attempts since Sep but no success).

I can isolate some of the fixes to a new PR for you guys to review in the coming 2-3 days, if that sounds ok.

[utensil]

There's one more issue to discuss: the version number.

I'm seeing 4 versions ever released on https://pypi.org/project/galgebra/#history , namely 0.4.1, 0.4.2, 0.4.2.1, 0.4.2.2 . In my understanding of https://semver.org/ , the releases before 1.0 is following 0.MAJOR.MINOR.PATCH, since this version will add Python 3 support, it seems that we can bump the MINOR, so the version number will be 0.4.3, is that right?

And setup.py is currently not specifying the version correctly (it says 0.4.1.1), and it states only 'Programming Language :: Python :: 2.7' is supported. These places needs to be updated in the version bump as well (just stating the obvious...).

[utensil]

@utensil I seem to have managed to get the pypi deployment to work just about with my credentials
https://pypi.org/manage/project/galgebra/releases/

Great!

P.S. I'm a little confused by the failed runs on Travis: