title: Spyder doesn't detect changes in imported python files
body: <p>I'm using Spyder 3.2.4 (Python 3.6). Spyder doesn't detect changes in imported python files. For example:</p>
  
  <p><em>test2.py:</em></p>
  
  <pre><code>def func():
      return 5
  </code></pre>
  
  <p><em>test1.py:</em></p>
  
  <pre><code>import test2
  
  a = test2.func()
  print(a)
  </code></pre>
  
  <p>When I wrote those classes, and saved them (in the same working directory), and ran <em>test1.py</em> the output was <code>5</code>.</p>
  
  <p>BUT when I change the function in <em>test2.py</em>, to like:</p>
  
  <pre><code>def func():
      return 10
  </code></pre>
  
  <p>Save it, and then run <em>python1.py</em>, I still get <code>5</code>. Only when I save, exit the IDE, and return, I will get the changed code (<code>10</code>). </p>
  
  <p>This behavior is going on since I started using Spyder (few months by now), and it's super annoying. Help would be appreciated. </p>