add @nullable annotations to class constructors

Author: Cliffus

expandabletextview/src/main/java/at/blogc/android/views/ExpandableTextView.java

@@ -58,12 +58,12 @@ public ExpandableTextView(final Context context)
         this(context, null);
     }
 
-    public ExpandableTextView(final Context context, final AttributeSet attrs)
+    public ExpandableTextView(final Context context, @Nullable final AttributeSet attrs)
     {
         this(context, attrs, 0);
     }
 
-    public ExpandableTextView(final Context context, final AttributeSet attrs, final int defStyle)
+    public ExpandableTextView(final Context context, @Nullable final AttributeSet attrs, final int defStyle)
     {
         super(context, attrs, defStyle);