title: Gradle eclipse task doesn't add proper gradle nature
body: <p>I have the following project structure:</p>
  <ul>
  <li>root-gradle (<code>build.gradle</code>)
  <ul>
  <li>project-group1 (no build file)
  <ul>
  <li>project1 (<code>build.gradle</code>)</li>
  <li>project2 (<code>build.gradle</code>)</li>
  <li>...</li>
  </ul>
  </li>
  <li>project-group2 (no build file)
  <ul>
  <li>...</li>
  </ul>
  </li>
  </ul>
  </li>
  </ul>
  <p>So happens that I have to recreate Eclipse projects often. I run command:</p>
  <pre><code>gradle cleanEclipse eclipse
  </code></pre>
  <p>After a number of runs &quot;eclipse&quot; task stops working as expected. Namely, it does not add gradle nature to the projects anymore and does not recognize</p>
  <pre><code>sourceCompatibility = 1.6
  </code></pre>
  <p>anymore attempting to build everything with 1.8 version of Java.</p>
  <p>I added the following to the root <code>build.gradle</code>:</p>
  <pre><code>allprojects {
      sourceCompatibility = 1.6
      eclipse.project {
          natures 'org.springsource.ide.eclipse.gradle.core.nature'
      }
      // more stuff here ...
  }
  </code></pre>
  <p>This helped with the root project, but had no effect on any other project.
  I added the same thing to subprojects with the same unsatisfactory result.
  I have to say than even after the nature had been added to the root project and Gradle plugin options became available for the root again I still don't see the &quot;G&quot; icon.</p>
  <p>So it looks like I have 2 problems with the gradle setup.</p>
  <ol>
  <li><p>Disappearance of the gradle nature. After a few runs Eclipse stops recognizing gradle projects. I wouldn't even face the second problem if that worked properly.</p>
  </li>
  <li><p>Some problem with my gradle build files or projects layout as my settings don't seem to take effect on subprojects.</p>
  </li>
  <li><p>Missing &quot;G&quot; icon for the project with restored Gradle nature.</p>
  </li>
  </ol>