adding removeAll to more closely mirror arraylist methods

CONTRIBUTING.md

@@ -11,6 +11,10 @@ When describing an issue, be precise:
 * What happened? What do you think should have happened?
 * On what Android version does this issue occur?
 
+# Asking Questions
+
+Asking questions should preferably be done on a dedicated forum such as [StackOverflow](http://stackoverflow.com/). This is an issue tracker after all. 
+
 # Contributing code
 
 ## Please do!
@@ -32,4 +36,4 @@ I'm happy to view and accept pull requests. However, it is important to follow t
 * **Do not** put any `@author` comment. Git keeps track of all your changes and `@author` does more harm than good.
 * **Do not** issue a pull request into the `master` branch.
 * Try to keep the diff as small as possible. For example, be aware of auto formatting.
-* All files should have the Apache 2 License header.
+* All files should have the Apache 2 License header.

lib-core/src/main/java/com/nhaarman/listviewanimations/ArrayAdapter.java

@@ -24,6 +24,7 @@
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Iterator;
 import java.util.List;
 
 /**
@@ -136,6 +137,20 @@ public T remove(final int location) {
         return result;
     }
 
+    public boolean removeAll(@NonNull Collection<?> c) {
+        boolean modified = false;
+        Iterator<?> e = this.mItems.iterator();
+        while (e.hasNext()) {
+            if (c.contains(e.next())) {
+                e.remove();
+                modified = true;
+            }
+        }
+        if(modified)
+            this.notifyDataSetChanged();
+        return modified;
+    }
+
     @Override
     public void swapItems(final int positionOne, final int positionTwo) {
         T firstItem = mItems.set(positionOne, getItem(positionTwo));