#539 Pointerbug in Nvidia driver

[Henrik Andersson]

A bug in the way a custom pointer hotspot is handled has been found,
Making the hotspot reset to top left corner of pointer bitmap,
Instead of where the application specifies it.
Bug is found via zunepaint, where the fill tool hotspot should be at the bottom of
The bitmap, deluxepaint style, but is at topleft corner, in the translucent area
Making aiming the tool tricky.

Found on nvidia driver, works normal on vesa mode, native icaros 2.1.3