Get it kind of working but it crashes in windowDidResignMain, not sure why that if statement is there

Add comments, force hotkey window to enter traditional fullscreen

Allow borderless windows glued to a screen edge to enter fullscreen mode. They can't enter Lion fullscreen mode because they're auxiliary windows (which allows them to appear over other fullscreen windows), but they cannot enter Lion fullscreen mode themselves. However, they're fine with traditional fullscreen, which I think is more useful for a hotkey window anyway since it won't change spaces on you.
Make the hotkey window go all the way off the screen. It was incorrectly using the screen's visible frame to compute its offscreen position. Fixes bug 2638