Correct servo limits - Improve servo life

For the past year I have been setting slightly conservative lower limit on servos shipped and I noticed almost none failed. This happens because when servo hits lower limit of retraction - it may pull on the cable if limit not correctly set in the menu. This, apparently, will wear out servo sooner.

Call to action: after completing your install - pay close attention to lower limit setting. Cable must not be loose, but do not add extra clicks to the setting past that "barely touching the cable base" moment"