Use InnoSetup to create Windows installers from AppVeyor

[Razican]

Seems that InnoSetup is included by default in AppVeyor to create the Windows installer. We should use it and automatically add it to our release. Some links:

• https://www.appveyor.com/docs/build-environment/
• http://help.appveyor.com/discussions/problems/4482-chocolatey-package-install-failure

[Razican]

This will obviously change now that we do not use AppVeyor for Windows builds.

[Razican]

Maybe we should use chocolatey?

Not sure, but I'm moving this to 0.7.0.