3.1 release

[joeraz]

I'm thinking it might be time for a 3.1 release.

My biggest concern is the fact that AppVeyor's ability to generate the localization files has broken (issues #375 and #324), so we can't get the localization files on Windows packages. I do not currently know how to fix this (I tried a lot, but the best I could do was comment the lines in the AppVeyor config, so it doesn't break everything else).

Any other inclusions/comments?

[joeraz]

I reached out to AppVeyor support last weekend as I have not been able to figure out what changed in their environment to make GNU Gettext fail.

If I don't hear anything back from them, I'm just going to proceed with this release as-is next weekend.

[joeraz]

Going to have to wait a couple more days. Not quite ready - I'll try to get the release out during the week.

[joeraz]

All done. 3.1 released.