title: DllNotFoundException in unity3d plugin for c++ dll
body: <p>I am working on the Unity Plugin project and try to import the c++ native dll from c# file.
  But I keep getting dllnotfoundexception.</p>
  
  <p><strong>c++ dll code: <br/></strong></p>
  
  <pre><code>extern "C" {
  extern __declspec( dllexport ) bool IGP_IsActivated();
  }
  </code></pre>
  
  <p><strong>c# code: <br/></strong></p>
  
  <pre><code>[DllImport("mydll")]
      private static extern bool IGP_IsActivated();
  </code></pre>
  
  <p>Dll is in place and FIle.Exists work properly. All dependent dlls are present at same hierarchy, but I still end up in dllnotfound exception.</p>
  
  <p>Any help, much appreciated!!</p>