Added Observable.timeout wrappers to scala adapter

Added the four timeout methods on Observable in the Scala adaptor. Note
for the java/scala type interop:
http://stackoverflow.com/q/20912151

Author: hura

language-adaptors/rxjava-scala/src/main/scala/rx/lang/scala/Observable.scala

@@ -1600,6 +1600,81 @@ trait Observable[+T]
     toScalaObservable[T](asJavaObservable.throttleLast(intervalDuration.length, intervalDuration.unit, scheduler))
   }
 
+  /**
+   * Applies a timeout policy for each item emitted by the Observable, using
+   * the specified scheduler to run timeout timers. If the next item isn't
+   * observed within the specified timeout duration starting from its
+   * predecessor, observers are notified of a `TimeoutException`.
+   * <p>
+   * <img width="640" src="https://raw.github.com/wiki/Netflix/RxJava/images/rx-operators/timeout.1.png">
+   *
+   * @param timeout maximum duration between items before a timeout occurs
+   * @return the source Observable modified to notify observers of a
+   *         `TimeoutException` in case of a timeout
+   */
+  def timeout(timeout: Duration): Observable[T] = {
+    toScalaObservable[T](asJavaObservable.timeout(timeout.length, timeout.unit))
+  }
+
+  /**
+   * Applies a timeout policy for each item emitted by the Observable, using
+   * the specified scheduler to run timeout timers. If the next item isn't
+   * observed within the specified timeout duration starting from its
+   * predecessor, a specified fallback Observable produces future items and
+   * notifications from that point on.
+   * <p>
+   * <img width="640" src="https://raw.github.com/wiki/Netflix/RxJava/images/rx-operators/timeout.2.png">
+   *
+   * @param timeout maximum duration between items before a timeout occurs
+   * @param other fallback Observable to use in case of a timeout
+   * @return the source Observable modified to switch to the fallback
+   *         Observable in case of a timeout
+   */
+  def timeout[U >: T](timeout: Duration, other: Observable[U]): Observable[U] = {
+    val otherJava: rx.Observable[_ <: U] = other.asJavaObservable
+    val thisJava = this.asJavaObservable.asInstanceOf[rx.Observable[U]]
+    toScalaObservable[U](thisJava.timeout(timeout.length, timeout.unit, otherJava))
+  }
+
+  /**
+   * Applies a timeout policy for each item emitted by the Observable, using
+   * the specified scheduler to run timeout timers. If the next item isn't
+   * observed within the specified timeout duration starting from its
+   * predecessor, the observer is notified of a `TimeoutException`.
+   * <p>
+   * <img width="640" src="https://raw.github.com/wiki/Netflix/RxJava/images/rx-operators/timeout.1s.png">
+   *
+   * @param timeout maximum duration between items before a timeout occurs
+   * @param scheduler Scheduler to run the timeout timers on
+   * @return the source Observable modified to notify observers of a
+   *         `TimeoutException` in case of a timeout
+   */
+  def timeout(timeout: Duration, scheduler: Scheduler): Observable[T] = {
+    toScalaObservable[T](asJavaObservable.timeout(timeout.length, timeout.unit, scheduler.asJavaScheduler))
+  }
+
+  /**
+   * Applies a timeout policy for each item emitted by the Observable, using
+   * the specified scheduler to run timeout timers. If the next item isn't
+   * observed within the specified timeout duration starting from its
+   * predecessor, a specified fallback Observable sequence produces future
+   * items and notifications from that point on.
+   * <p>
+   * <img width="640" src="https://raw.github.com/wiki/Netflix/RxJava/images/rx-operators/timeout.2s.png">
+   *
+   * @param timeout maximum duration between items before a timeout occurs
+   * @param other Observable to use as the fallback in case of a timeout
+   * @param scheduler Scheduler to run the timeout timers on
+   * @return the source Observable modified so that it will switch to the
+   *         fallback Observable in case of a timeout
+   */
+  def timeout[U >: T](timeout: Duration, other: Observable[U], scheduler: Scheduler): Observable[U] = {
+    val otherJava: rx.Observable[_ <: U] = other.asJavaObservable
+    val thisJava = this.asJavaObservable.asInstanceOf[rx.Observable[U]]
+    toScalaObservable[U](thisJava.timeout(timeout.length, timeout.unit, otherJava, scheduler.asJavaScheduler))
+  }
+
+
   /**
    * Returns an Observable that sums up the elements of this Observable.
    *
@@ -1894,21 +1969,21 @@ trait Observable[+T]
   }
 
   /**
-   * Invokes an action if the source Observable calls <code>onError</code>.
+   * Invokes an action if the source Observable calls `onError`.
    *
    * @param onError the action to invoke if the source Observable calls
-   *                <code>onError</code>
+   *                `onError`
    * @return the source Observable with the side-effecting behavior applied
    */
   def doOnError(onError: Throwable => Unit): Observable[T] = {
     toScalaObservable[T](asJavaObservable.doOnError(onError))
   }
 
   /**
-   * Invokes an action when the source Observable calls <code>onCompleted</code>.
+   * Invokes an action when the source Observable calls `onCompleted`.
    *
    * @param onCompleted the action to invoke when the source Observable calls
-   *                    <code>onCompleted</code>
+   *                    `onCompleted`
    * @return the source Observable with the side-effecting behavior applied
    */
   def doOnCompleted(onCompleted: () => Unit): Observable[T] = {