3D Printer Bed Leveling

http://www.protoparadigm.com/news-updates/3screw-bed-leveling-and-the-importance-of-a-level-print-bed-on-a-3d-printer/
http://www.tridimake.com/2015/12/bed-leveling-tramming-sensors.html	Steps through entire state of the art/tech tree of choices.
http://www.tridimake.com/2015/12/tribed-fully-automatic-bed-leveling-and-z-offset-adjustment.html
http://hackaday.com/2014/04/15/automated-bed-leveling-for-3d-printers-is-now-solved/
http://www.instructables.com/id/Mach3-Zero-Probe-Tool/