fix app starting offscreen

[Araxeus]

Aims to fix issues such as #193 #542, probably fix #517

checks if the app is completely offscreen (x / width) or if the titlebar is offscreen (y / height)

checks if window is inside the display closest to the given point

Tested on multiple monitor setup and works perfectly

[Araxeus]

now also check if the titlebar y coordinate is offscreen

[Araxeus]

f5e22b5 made it so that the app validate the coordinates if they are inside the coordinates of the closest display to the given point

• get saved absolute coordinates (grid start point (0,0) is the top left corner of the primary monitor)
• get monitor closest to said point
• check if given coordinates is inside the rectangle of the closest monitor

monitor rectangle top left is (bounds.x, bounds.y)
and obviously bottom right is (bounds.x + bounds.width, bounds.y + bounds.height)

[th-ch]

Looks good, just one question before merging!