Fixed npe

Author: nikartx

support/src/main/java/com/github/nikartm/support/StripedProcessButton.java

@@ -16,7 +16,7 @@
 public class StripedProcessButton extends AppCompatButton implements Animatable {
 
     private AnimatedStripedDrawable stripedDrawable;
-    private State state;
+    private State state = State.STOP;
 
     private long startAnimDuration = Constants.NO_INIT;
     private long stopAnimDuration = Constants.NO_INIT;