Preset browser items offset from mouse

[d.healey]

It seems the list items don't quite match up with the mouse position.

[d.healey]

Oh actually this is because I'm using the listAreaOffset property to offset the Y axis. Since it was me that implemented this I guess I better try and find a solution to the mouse not being offset too :p

[d.healey]

Fixed - https://github.com/christophhart/HISE/pull/368