About page + quit button

I added an about page linking to the release page.
I also moved the "Quit" option as far from the mouse as possible, just like it was in the original branch.

Windows 10 fixes

I fixed some of the quirks this program had when executed on Win10 (Vista or later, really, judging from the code), such as support for High DPI and the fact that windows have an invisible border around them in Aero/DWM.