gueei/AndroidBinding — pull request #4 by eji (2013-10-13 16:13:51+00:00)
Title: fixed to don't notify observer objects that have been collected by GC

In rare cases, when a value is set to an observable object, NullPointerException occurs.

In the WeakList#toArray method, ``itemArray[i].get()`` may return null if the GC is executed between A and B.
```java
public Object[] toArray() {
synchronized(this){
removeReleased();
@SuppressWarnings("unchecked")
WeakReference[] itemArray = items.toArray(new WeakReference[0]); // (A)
int len = itemArray.length;
Object[] eArray = new Object[len];
for(int i=0; i