title: xtext imports not working
body: <p>I'm just getting started with xtext 2.9.2 on IntelliJ IDEA 2016.3. I try to follow the simple <a href="http://www.eclipse.org/Xtext/documentation/102_domainmodelwalkthrough.html#run-generated-plugin%20xx" rel="nofollow noreferrer">15 Minutes Tutorial</a>. The first iteration was fine, but the imports do not work.</p>
  
  <p>I have created 2 repos on github:</p>
  
  <ul>
  <li><a href="https://github.com/tmtron/xtext.15minTutorial" rel="nofollow noreferrer">the project which defines the DSL</a></li>
  <li>and <a href="https://github.com/tmtron/xtext.15minTutorial.project" rel="nofollow noreferrer">the project that uses the generated editor</a>
  
  <ul>
  <li>when I define everything in a <a href="https://github.com/tmtron/xtext.15minTutorial.project/blob/master/src/singleFile.dmodel" rel="nofollow noreferrer">singleFile</a> it is okay</li>
  <li>but when I split the model into 3 files (same like in the example), then the imports are not recognized: my DSL editor reports an error
  
  <ul>
  <li>e.g. <a href="https://github.com/tmtron/xtext.15minTutorial.project/blob/master/src/commons.dmodel#L3" rel="nofollow noreferrer">commons.dmodel</a> will complain: <code>couldn't resolve reference to type String</code> </li>
  <li>The String data-type is defined here: <a href="https://github.com/tmtron/xtext.15minTutorial.project/blob/master/src/datatypes.dmodel" rel="nofollow noreferrer">datatypes.dmodel</a></li>
  </ul></li>
  </ul></li>
  </ul>
  
  <p>How does xtext try to resolve the imports? e.g. does it automatically look for all my *.dmodel files in the whole project?</p>