Support the PanelOne controller

This is a simple Open Source LCD controller for RAMPS that is
distributed with the Think3dPrint3d Mini Kossel kits.

The firmware changes are tested on RAMPS (it only effects the RAMPS part of pins.h) both enabled and disabled.

More details on the PanelOne:

KiCAD source files are here:
https://github.com/T3P3/PanelOne

Info on the RepRap Wiki:
http://reprap.org/wiki/PanelOne

Blog post with more details:
http://blog.think3dprint3d.com/2014/08/panelone-lcd-screen-for-33v-and-5v.html

Case design tutorial in OpenSCAD
http://blog.think3dprint3d.com/2014/04/OpenSCAD-PanelOne-case-design.html