Added a return home method and broke out the error query into its own method.
Syntax change to _check_limit_reached()
Moved the set_pos_as_origin() to main() b/c... shold eventually move all main() methods to code_tools
Debugged the return home method and tested with zero volts on pin 1. Also set pin2 for the + limit.
Merge branch 'master' into user_interface_version
Trying to keep user_interface feature branch up to date with the rest, but I don't want to
have to debug from the UI feature branch.

Good lesson in conflict management too...xxdiff

Conflicts:
	main.py