Add Motherboard variant 64 - STB V1.1

Definition for the graphic LCD are already in it, they will not harm the
configuration as they are only defined constants
Add pins for Motherboard variant 64

These definition contain also the definition for the graphics LCD.
Merge pull request #1 from illuminarti/Fix_E_Speed

Fix step rate bug (especially for retraction)
Merge pull request #411 from STB3/Marlin_w_STB_Board_support

Add STB board support to Marlin (next step towards graphic LCD implementation)
Merge remote-tracking branch 'upstream/Marlin_v1' into Marlin_v1