2.18.0 Release

[joeraz]

It's been a while, and since the last release, I've added several major new features, so I'm thinking I should prepare a new release relatively soon. Anyone have any objections or anything they want to add in?

Here's what I'd still like to do:

• As of right now, there are only 15 games left still missing rules in the documentation. I think it's time to finally finish the docs.
• The "Stuck Notification" option can use some extra testing. It's working for all the games I've tried, and I've fixed the ones it isn't working for. But there are over 1,000 games, and I haven't played every single one of them.
• Play with AppVeyor a bit. I think removing the PyInstaller onefile option should eliminate the antivirus false positives, and I'd like to test that. I'd also like to see if I can get AppVeyor to deliver a few additional variants of the Windows Installer, like one that uses an older Python version for older Windows versions.
• Maybe a few more minor fixes, but I don't want to try and cram any more big items into this release.