javadocs: add @SInCE annotations to new methods; fix formatting, polish wording for new Subscriber constructor

Author: DavidMGross

src/main/java/rx/Observable.java

@@ -4538,6 +4538,7 @@ public final <R> Observable<R> flatMap(Func1<? super T, ? extends Observable<? e
      *         by the source Observable and merging the results of the Observables obtained from this
      *         transformation
      * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
+     * @since 1.0.6
      */
     @Beta
     public final <R> Observable<R> flatMap(Func1<? super T, ? extends Observable<? extends R>> func, int maxConcurrent) {

src/main/java/rx/Subscriber.java

@@ -46,14 +46,18 @@ protected Subscriber() {
     protected Subscriber(Subscriber<?> op) {
         this(op, true);
     }
+
     /**
-     * Construct a subscriber by using the other subscriber for backpressure
-     * and optionally sharing the underlying subscriptions list.
-     * <p>To retain the chaining of subscribers, the caller should add the
-     * created instance to the op via {@code add()}.
+     * Construct a Subscriber by using another Subscriber for backpressure and optionally sharing the
+     * underlying subscriptions list.
+     * <p>
+     * To retain the chaining of subscribers, add the created instance to {@code op} via {@link #add}.
      * 
-     * @param op the other subscriber
-     * @param shareSubscriptions should the subscription list in op shared with this instance?
+     * @param op
+     *            the other Subscriber
+     * @param shareSubscriptions
+     *            {@code true} to share the subscription list in {@code op} with this instance
+     * @since 1.0.6
      */
     protected Subscriber(Subscriber<?> op, boolean shareSubscriptions) {
         this.op = op;