RigidPanel LCD and Full Graphic LCD support

Both the RigidPanel LCD and Full Graphic LCD support compile in successfully, and the RigidPanel LCD has been thoroughly tested.  In addition to the LCD support, I created a "predefined mechanics" structure in Configuration.h that will let the RigidBot and other kit/preassembled machines define all the build volume, acceleration, jerk, limits, etc. into a block that can be selected with a single #define.  There is also an automated build script in configuration_examples/rigidbot/ that can be used to quickly build many permutations of firmware features.  Still need testing on the RepRap Discount Full Graphic LCD, and compiling in the Arduino GUI.