title: errors with multimap (key type is std::string)
body: <p>I've been having problems with getting multimap to work. I'll just show the code and describe the problem:</p>
  
  <pre><code>    #include &lt;string&gt;
      ...
  
      multimap&lt;std::string, pinDelayElement&gt; arcList
      pinDelayElement pde;
      std:string mystring = "test"
      arcList[mystring] = pde;
  </code></pre>
  
  <p>However, when I compile, the last line gives me the following error:</p>
  
  <blockquote>
    <p>error C2676: binary '[' : 'std::multimap&lt;_Kty,_Ty>' does not define this operator or a conversion to a type acceptable to the predefined operator
            with
            [
                _Kty=std::string,
                _Ty=Psdfwr::pinDelayElement
            ]</p>
  </blockquote>
  
  <p>Does anyone know something I might be doing wrong?</p>