title: iGUI dll could not be found
body: <p>Previously, I was able to build an iOS project with Unity 4.6.2, but I can't with Unity 5.1.1. I get an <code>iGUI</code> dll could not be found error:</p>
  
  <pre><code>ArgumentException: The Assembly UnityEditor is referenced by iGUI ('Assets/lib/igui/Runtime/iGUI.dll'). But the dll is not allowed to be included or could not be found.
  UnityEditor.AssemblyHelper.AddReferencedAssembliesRecurse (System.String assemblyPath, System.Collections.Generic.List`1 alreadyFoundAssemblies, System.String[] allAssemblyPaths, System.String[] foldersToSearch, System.Collections.Generic.Dictionary`2 cache, BuildTarget target) (at /Users/builduser/buildslave/unity/build/Editor/Mono/AssemblyHelper.cs:154)
  UnityEditor.AssemblyHelper.AddReferencedAssembliesRecurse (System.String assemblyPath, System.Collections.Generic.List`1 alreadyFoundAssemblies, System.String[] allAssemblyPaths, System.String[] foldersToSearch, System.Collections.Generic.Dictionary`2 cache, BuildTarget target) (at /Users/builduser/buildslave/unity/build/Editor/Mono/AssemblyHelper.cs:160)
  UnityEditor.AssemblyHelper.FindAssembliesReferencedBy (System.String[] paths, System.String[] foldersToSearch, BuildTarget target) (at /Users/builduser/buildslave/unity/build/Editor/Mono/AssemblyHelper.cs:192)
  UnityEditor.HostView:OnGUI()
  </code></pre>
  
  <p>What could be the issue?</p>