Provide CI integration for Windows builds.

[flihp]

If you couldn't tell from #8 and #22 I'm a big fan of continuous integration. Figured we can give windows the same treatment given to Linux by using AppVeyor. I've some experience here on account of the tpm2-software project and our support of both Linux and Windows for our TSS2. We use appveyor for our CI on windows and have had pretty good results.

[bradlitterell]

@flihp - Noticed this old issue. If I understand correctly this issue is to provide CI integration of the Windows builds, and changed the title accordingly. If I misunderstood the overarching request, please correct me.