On focus loss in Windows 7, app regains Windows border.

[JosephCoppola]

When the BorderlessWindow app loses focus, it gains it's borders back. This only occurs on Windows 7.

[JosephCoppola]

Spent all day trying to get something halfway decent.

Still not sure what the root cause of the issue is here but I found if on Window Focus (WM_SETFOCUS) and Focus Loss (Check state in WM_ACTIVATE) if I set the window style again and redraw the frame it will return to the borderless state. The frame flashes briefly, but considering Windows 7 is nearly a decade old and is the lowest OS we are supporting this is a decent trade off.