title: Rxjs swallows errors
body: <p>Having a simple <code>Rxjs</code> stream, i faced this situation:</p>
  
  <pre><code>Rx.Observable
    .fromArray([1,2,3,4,5,6])
  // if commented from here 
    .windowWithCount(2, 1)
    .selectMany(function(x) {
      return x.toArray();
    })
  // to here .. the error bubbles up
    .subscribe(function(x) {
      console.log('x:',x)
      throw new Error("AAHAAHHAHA!");  
    });
  </code></pre>
  
  <p>with the <code>windowWithCount + selectMany</code> the error is silently catched internally and isn't catchable and it isn't notified in console neither </p>
  
  <p>commenting those 2 blocks the error is notified on console at least<br>
  I don't think this is supposed to be, or am i missing something?<br>
  <a href="http://jsbin.com/gujuyadesa/2/edit?js,console" rel="nofollow">here the jsbin</a></p>