Add AppVeyor support

[JayFoxRox]

This adds support for AppVeyor builds and deployment of the 32 bit MinGW builds to this repository.

Problems which need an issue after merge:

• MSVC build is broken. I could not make this work due to various errors with trying to put it in x86 mode; but not even x64 compilation worked. I have no idea why that is.
• The binaries are not static yet, so they might not even work without the respective libraries.
• The MinGW build puts a "a.exe" in it's output folder. I'm not sure where this one comes from, but it's the reason why I only explicitly copy "swe1r-.exe" instead of ".exe".
• swe1r-patcher.exe might be confusing to people (who are looking for swe1r-loader.exe). Ideally these tools should be merged into a single tool, or a warning should be displayed if swe1r-patcher.exe is used incorrectly.