minor updates to ChromatinCropper
Added more dot property computations as separate step before saving data.  Code now builds histograms from current data as user progresses.
ChromatinCropper before modifying to select save regions prior to analysis (rather than during save step and removing the unanalyzed regions0
Made Gaussian fits optional in findcluster3D, moved selection of good regions to before Analysis for ChromatinCropper
updated analysis options in ChromatinCropper.
added autocycle and more export features to ChromatinCropper