generation requires reference implementation project to be present in workspace

[bbouldin]

Clicking the "Generate" link on the Overview tab results in the following error when any of the original reference implementation projects are absent from the Eclipse workspace:

  
  java.lang.NullPointerException
  In recurse/mainJetFile2.prod
  	[13,1] : <c1:iterate select="$target/createFile" var="createFile">
  	[20,1] : <c1:copyFile target="{$xform/@xformId}/src/main/resources/{$xform/@xformDir}/{$createFile/@template}" src="{$createFile/@src}" srcContext="workspace" replace="false" binary="true"/>