default destRange +2pixes;

also fixing the logic of startFrame, so that if it's specified (>1) then
that overrules the gaze-skipping mechanism.
working version; fixing many issues with the videos

- videogazeoffset is estimated at 600msec

- some sigs will shift slightly in location; implemented a +2pix rule in
the video2aoi.py code; also can use destRange to increase the search
range