title: Exception_Notification is not aware of RecordNotFound exceptions
body: <p>I'm trying to use exception_notification for the first time. I watched the Railscast and followed instructions from the author in <a href="http://smartinez87.github.io/exception_notification/" rel="nofollow">http://smartinez87.github.io/exception_notification/</a>. Everything seems to work fine with some sort of exceptions but not with others. </p>
  
  <p>I tested and received email error notificatios from my dev environment with errors such as <code>"An ActionView::Template::Error occurred in static_pages#home:</code>". But, there are some Exceptions such as <code>RoutingException</code> and <code>RecordNotFound</code> that are not being catched by ExceptionNotification, and I don't know why, as I have not any rescue_from strategy of any kind in my application_controller.</p>
  
  <p>I'm using rails 3.2.12 and checked the middleware stack array, and I can see ExceptionNotification is just the last one, and it seems that some kind of exceptions does not go their way down the stack, so Exception Notification is not aware of them.  </p>
  
  <p>So, the question are: what am i doing wrong? what is the difference between <code>ActionController::RoutingError</code> or <code>ActiveRecord::RecordNotFound</code>  which are not catched by ExceptionNotification and <code>ActionView::Template::Error</code> which is catched and causes Exception Notification to send the notification email to my inbox.</p>
  
  <p>Thanks in advance</p>