Merge branch 'dev' of https://github.com/uArm-Developer/UArmForArduino into dev

Author: altjz

examples/Metal/calibration.png

@@ -1,5 +1,5 @@
 name=uArmLibrary
-version=2.1.4
+version=2.2.1
 author=UFactory <developer@ufactory.cc>
 maintainer=Joey Song <joey@ufactory.cc>, Alex Tan<alex@ufactory.cc>, Dave Corboy<dave@corboy.com>
 sentence=uArm Library for Arduino