Added an option to only check the X or Y distance
onlyX / onlyY
Thanks, that's a good use case I hadn't considered.
I should clean up the checkHoriz and checkVert options to be a bit more consistent (I'm thinking maybe sameX: true instead of checkHoriz: false, and similar for sameY vs checkVert
Quick update: This feature has now been released to plugins.jquery.com and Bower as version 1.3.0.