Added link urls to the msdn descriptions

Author: jmhofer

rxjava-core/src/main/java/rx/Observable.java

@@ -2308,12 +2308,12 @@ public Observable<T> first(Func1<? super T, Boolean> predicate) {
      *            The default value to emit if the source Observable doesn't emit anything.
      * @return an Observable that emits only the very first item from the source, or a default value 
      *         if the source Observable completes without emitting a single item.
-     * @see <a href="">MSDN: Observable.FirstOrDefault</a>
+     * @see <a href="http://msdn.microsoft.com/en-us/library/hh229320%28v=vs.103%29.aspx">MSDN: Observable.FirstOrDefault</a>
      */
     public Observable<T> firstOrDefault(T defaultValue) {
         return create(OperationFirstOrDefault.firstOrDefault(this, defaultValue));
     }
-    
+
     /**
      * Returns an Observable that emits only the very first item emitted by the source Observable
      * that satisfies a given condition, or a default value otherwise.
@@ -2324,12 +2324,12 @@ public Observable<T> firstOrDefault(T defaultValue) {
      *            satisfies the given condition.
      * @return an Observable that emits only the very first item from the source that satisfies the
      *         given condition, or a default value otherwise.
-     * @see <a href="">MSDN: Observable.FirstOrDefault</a>
+     * @see <a href="http://msdn.microsoft.com/en-us/library/hh229759%28v=vs.103%29.aspx">MSDN: Observable.FirstOrDefault</a>
      */
     public Observable<T> firstOrDefault(Func1<? super T, Boolean> predicate, T defaultValue) {
         return create(OperationFirstOrDefault.firstOrDefault(this, predicate, defaultValue));
     }
-    
+
     /**
      * Returns an Observable that emits items emitted by the source Observable so long as a
      * specified condition is true.