Add some hack to fix window size, shadow, position problem.

Fix window size when window will be drawn out side of screen.
Hack window position by an additional toplevel widget.
using resizeEvent to listen the size change, setMask to override
posible kwin shadow. Using event filter to resize the window to
correct size.
Merge pull request #1 from csslayer/master

Add some hack to fix window size, shadow, position problem.