Fix some javadoc issues

Author: tokudu

library/src/main/java/com/sothree/slidinguppanel/ScrollableViewHelper.java

@@ -7,7 +7,7 @@
 
 /**
  * Helper class for determining the current scroll positions for scrollable views. Currently works
- * for ListView, ScrollView & RecyclerView, but the library users can override it to add support
+ * for ListView, ScrollView and RecyclerView, but the library users can override it to add support
  * for other views.
  */
 public class ScrollableViewHelper {

library/src/main/java/com/sothree/slidinguppanel/SlidingUpPanelLayout.java

@@ -921,7 +921,7 @@ public boolean onInterceptTouchEvent(MotionEvent ev) {
     }
 
     @Override
-    public boolean onTouchEvent(@NonNull MotionEvent ev) {
+    public boolean onTouchEvent(MotionEvent ev) {
         if (!isEnabled() || !isTouchEnabled()) {
             return super.onTouchEvent(ev);
         }
@@ -935,7 +935,7 @@ public boolean onTouchEvent(@NonNull MotionEvent ev) {
     }
 
     @Override
-    public boolean dispatchTouchEvent(@NonNull MotionEvent ev) {
+    public boolean dispatchTouchEvent(MotionEvent ev) {
         final int action = MotionEventCompat.getActionMasked(ev);
 
         if (!isEnabled() || !isTouchEnabled() || (mIsUnableToDrag && action != MotionEvent.ACTION_DOWN)) {