HOWTO.md

	Press SHIFT and draw on the image to select the area to zoom in. Press Z to goes back to full view.
	Press Z to zoom into the current annotation. Press N (next) and P (previous) to cycle thru annotations.
	Press SPACE to start drawing a new annotation. Press ESC to cancel, ENTER to save and go back to edit mode or SPACE to save and start another annotation. Press G to toggle guidelines.
	Press a key from 1 to 9 to change the label. Or press L and search by typing label's name or index.