Enable Appveyor CI on Windows

[ankostis]

So that any changes are also tested on Windows.

[ankostis]

@Byron I created the badge under your Appveyor account; please check it is correct and add smmap into your Appveyor projects,
Everyhthin passes OK!
[edit] I know the badge url is not the correct one.

[coveralls]

Coverage remained the same at 93.227% when pulling 1597a88 on ankostis:appveyor into 65989da on gitpython-developers:master.

[coveralls]

Coverage remained the same at 93.227% when pulling dfadc16 on ankostis:appveyor into 65989da on gitpython-developers:master.

[coveralls]

Coverage decreased (-0.5%) to 92.736% when pulling be5d426 on ankostis:appveyor into 65989da on gitpython-developers:master.

[Byron]

Thanks so much ! I think for these changes to come through, I would have to re-publish this package, which I cannot do anymore as I have lost access to my old, google-based login. The same holds true for gitdb.
Is it possible to specify dependencies via github URLS in the setup.py ? Then I could possibly republish GitPython pointing to GitDB, and push GitDB pointing to smmap via a github URL.

[ankostis]

Yes, it is possible to depend on Github[1][2], but it really worths the effort to have the packages in PyPi.
For development, there are other ways to force dependencies into local project folders instead of putting those projects as submodules.

[1] http://stackoverflow.com/questions/16584552/how-to-state-in-requirements-txt-a-direct-github-source
[2] http://stackoverflow.com/questions/32688688/how-to-write-setup-py-to-include-a-git-repo-as-a-dependency