Fixes firebase#134 and firebase#28. Using keyRef.updateChildren inste…

…ad of keyRef.setValue also fixes a huge amount of unnecessary 'onDataExited(DataSnapshot dataSnapshot)' events which has not been reported yet. keyRef.updateChildren understands if the data needs to be inserted or updated. No need to use setValue here. Since priorities are not relevant anymore (https://stackoverflow.com/questions/31577915/what-does-priority-mean-in-firebase) i decided to not consider them anymore.

common/src/main/java/com/firebase/geofire/GeoFire.java

@@ -28,17 +28,20 @@
 
 package com.firebase.geofire;
 
+import static com.firebase.geofire.util.GeoUtils.capRadius;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.logging.Logger;
+
 import com.firebase.geofire.core.GeoHash;
 import com.google.firebase.database.DataSnapshot;
 import com.google.firebase.database.DatabaseError;
 import com.google.firebase.database.DatabaseReference;
-import com.google.firebase.database.ValueEventListener;
 import com.google.firebase.database.GenericTypeIndicator;
-import java.lang.Throwable;
-import java.util.*;
-import java.util.logging.Logger;
-
-import static com.firebase.geofire.util.GeoUtils.capRadius;
+import com.google.firebase.database.ValueEventListener;
 
 /**
  * A GeoFire instance is used to store geo location data in Firebase.
@@ -172,14 +175,14 @@ public void setLocation(final String key, final GeoLocation location, final Comp
         updates.put("g", geoHash.getGeoHashString());
         updates.put("l", Arrays.asList(location.latitude, location.longitude));
         if (completionListener != null) {
-            keyRef.setValue(updates, geoHash.getGeoHashString(), new DatabaseReference.CompletionListener() {
+            keyRef.updateChildren(updates, new DatabaseReference.CompletionListener() {
                 @Override
                 public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {
                     completionListener.onComplete(key, databaseError);
                 }
             });
         } else {
-            keyRef.setValue(updates, geoHash.getGeoHashString());
+            keyRef.updateChildrenAsync(updates);
         }
     }
 
@@ -212,7 +215,7 @@ public void onComplete(DatabaseError databaseError, DatabaseReference databaseRe
                 }
             });
         } else {
-            keyRef.setValue(null);
+            keyRef.setValueAsync(null);
         }
     }