make it so that roi fails after plotting it
make it so that roi fails after plotting it

make it so that roi fails after plotting it so that users can better debug, ie they can tell if the ROI is just going off the screen or if it is completely out of the field of view.

stiphyMT/plantcv,danforthcenter/plantcv,danforthcenter/plantcv,stiphyMT/plantcv,stiphyMT/plantcv,danforthcenter/plantcv