v3.1.7	20170615
improve learning performence.

v3.1.6	20170613
support grove mini fan(use D8 port or D9 port)
fix the jerk of 4th axis in moving and playing mode
fix the unpredictable working of valve during the learning mode

v3.1.4	20170527
support grove ultrasonic(use D8 port)

v3.1.3 	20170525
fix bug: cannot release object from pump

v3.1.2 	20170505
First Release Version