bug fixed by adding check if MultiWidget exists
Merge branch 'bug-13978-Fix-CrashDueToUnavailableRenderwindow'
Setting a pixel value for the background in the output image.
Merge branch 'bug-14175-RemoveFutileCalculationOfBackgroundVolume'
Deleting a clipping plane causes a change of working data to another clipping plane.
If no other clipping plane exist the working data will be set to null.
Addes new MITK Error Logging changes.
Also some minor formatting changes.
Changed logic for enable/diable volume calculating.
Only if a segmentation is selected the volume of the clipped parts can be calculated.
Merge branch 'bug-12587-ExtendUsabilityOfClippingPlaneView'
Fixed some typos and removed CMake links
Merge branch 'bug-13772-add-FAQs'
Fixed reactivating the SegmentationView which missed to re-read the image related to the segmentation
Merge branch 'bug-14176-FixReactivatingSegmentationView'