Added a Threshold preview for Tensor reconstruction
Merge branch 'bug-14639-ShowThresholdPreviewInTensorReconstruction' into bug-14639-ShowThresholdPreviewInTensorReconstruction_ITK4
Merge branch 'bug-14639-ShowThresholdPreviewInTensorReconstruction_ITK4' into thresholdBug
remove threshold preview node when the plugin is deactivated
set threshold preview to helper object again
same for qball reconstruction. refresh wenn threshold preview is removed on deactivation
Merge remote-tracking branch 'origin/bug-14639-TresholdPreviewRemovedOnPluginDeactivation' into bug-18320-RecoverLostPreview
use typedef for diffusion type
Merge branch 'bug-18320-RecoverLostPreview'