Fix bug in correctLineShift which caused wrong shifts for some image sizes
Fix bug in correctLineShift which caused wrong shifts for some image sizes

There was a subtle by in correctLineShift which lead to the opposite
shift being applied for certain movie sizes, e.g. 1024 by 1024. This is
now fixed.

HarveyLab/Acquisition2P_class,HarveyLab/Acquisition2P_class