Cursor position is incorrect when cursor leaves the viewport

[TylerGlaiel]

If I move the mouse outside the viewport, it sometimes still shows up in the recorded gif at a random location. Mouse works fine when the mouse is in the viewport

[TylerGlaiel]

here's a clear example of the issue, mouse moves in a straight line here, and you can see it jumps from the bottom right to the side

[TylerGlaiel]

logical to physical point would do weird things when the mouse leaves the viewport, passing 0 here instead of hwnd fixes the issue

https://github.com/justinfrankel/licecap/pull/129