title: GMaven project from mvn archetype:generate doesn't `mvn compile`
body: <p>I generated an empty project with:</p>
  
  <p><code>mvn archetype:generate -DarchetypeGroupId=org.codehaus.gmaven.archetypes -DarchetypeArtifactId=gmaven-archetype-basic -DarchetypeVersion=1.4</code></p>
  
  <p>and it fails to <code>mvn compile</code> with a bunch messages <code>"package groovy.lang does not exist"</code>.</p>
  
  <p>(for <code>archetypeVersion</code> I just picked the last GMaven release version)</p>
  
  <p>What's wrong with my Maven/GMaven/Groovy?</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;!--
      Generated from archetype; please customize.
  --&gt;
  
  &lt;project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"&gt;
  
      &lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
  
      &lt;groupId&gt;a&lt;/groupId&gt;
      &lt;artifactId&gt;asd&lt;/artifactId&gt;
      &lt;name&gt;asd project&lt;/name&gt;
      &lt;version&gt;1.0-SNAPSHOT&lt;/version&gt;
  
      &lt;dependencies&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;junit&lt;/groupId&gt;
              &lt;artifactId&gt;junit&lt;/artifactId&gt;
              &lt;version&gt;3.8.2&lt;/version&gt;
              &lt;scope&gt;test&lt;/scope&gt;
          &lt;/dependency&gt;
      &lt;/dependencies&gt;
  
      &lt;build&gt;
          &lt;plugins&gt;
              &lt;plugin&gt;
                  &lt;groupId&gt;org.codehaus.gmaven&lt;/groupId&gt;
                  &lt;artifactId&gt;gmaven-plugin&lt;/artifactId&gt;
                  &lt;version&gt;1.4&lt;/version&gt;
                  &lt;configuration&gt;
                      &lt;providerSelection&gt;1.8&lt;/providerSelection&gt;
                  &lt;/configuration&gt;
                  &lt;executions&gt;
                      &lt;execution&gt;
                          &lt;goals&gt;
                              &lt;goal&gt;generateStubs&lt;/goal&gt;
                              &lt;goal&gt;compile&lt;/goal&gt;
                              &lt;goal&gt;generateTestStubs&lt;/goal&gt;
                              &lt;goal&gt;testCompile&lt;/goal&gt;
                          &lt;/goals&gt;
                      &lt;/execution&gt;
                  &lt;/executions&gt;
              &lt;/plugin&gt;
          &lt;/plugins&gt;
      &lt;/build&gt;
  
  &lt;/project&gt;
  </code></pre>