add command M666 for adjusting delta printer endstop position
Merge pull request #582 from hercek/upstream

add command M666 for adjusting delta printer endstop position
Update read me. Added comment about products that have a patent.
Fix the example delta configuration as someone forgot to do it.
Merge pull request #589 from wolfmanjm/upgrade

Fix the example delta configuration by adding DELTA_DIAGONAL_ROD_2