Preliminary fix issue in previous commit.

Use the "real" bit depth even for 16bit images by setting the sBit
attribute in the PNG format.

This allows for getting rid of the "image type" attribute. The set
function is stubbed in this version.

Add LV unit to Simulation/Rotation property.

This makes working with different bit depth much easier.

Save/Load is not yet working correctly!!!

Started to change ImgClass array type from DBL -> SGL.
It looks like that this leads to a performance boost.

Small code cleanups.

Not yet working correctly.

Improve ZernikeCtrl handling

without file dailog.

read and write imgclass.
rework imgclass form array and image.
clean up.
consitent set from image bit depth and image tpye integer.

Gernerate offline Image done.

Save Image to Disk for ImgClass.