added Dr. Lars Gerigk as CC

[SVN revision 20981]
FIX (#3202): Revert to stable behavior for CT images and perhaps problematic behavior for MRI

I just changed the behavior of the region growing tool to the behavior before revisions 18328/18345, where Daniel and Philipp tried to improve region growing on MR images.

I recognie that the origin of T1540 was also usage of region growing on MR data and that this is still not solved nicely. But with the recent behavior of the tool, region growing was neither useful on CT nor on MR data. Now it is at least useful on CT.

The following ideas sketch a solution:

• moving the mouse up and down changes the width of the gray value interval which is used to control the region growing algorithm
• the absolute distance of the mouse position from the initial mouse position is added/subtracted from the interval width (scaled by a fixed factor)
• to my knowledge, problems only arise when the screen borders are a limit for mouse movement (unlimited screen size would fix the problem)
• moving the visible mouse cursor back to the initial position after each mouse movement would make infinitely long mouse movements possible (the volume visualization module uses this trick, too)

An implementation problem is that we currently have no means of changing the mouse cursor position from the code location where mouse movement is evaluated for the region growing tool -- this is Qt independent code. However, there is already a class for changing the mouse cursor icon independently of Qt (mitk::ApplicationCursor). This class could be enhanced to also provide and manipulate the absolute mouse cursor position.

Proposed changes to implement described feature.

Now attached the right patch -- previous one was for a different issue.

[SVN revision 20983]
FIX (#3202): enhanced mouse movement area by constantly resetting the mouse position after each move

Region growing feature should be better usable now. I'm closing this issue now until there is new feedback from medical users.