update sentences

Author: Alice Pintus

library.properties

@@ -2,7 +2,7 @@ name=Stepper
 version=1.1.2
 author=Arduino
 maintainer=Arduino <[email protected]>
-sentence=Allows Arduino boards to control a variety of stepper motors. For all Arduino boards.
+sentence=Allows Arduino boards to control a variety of stepper motors. 
 paragraph=This library allows you to control unipolar or bipolar stepper motors. To use it you will need a stepper motor, and the appropriate hardware to control it.
 category=Device Control
 url=http://www.arduino.cc/en/Reference/Stepper