Fixes #55 - Stack overflow in "Run as Clojure REPL"

ccw.core/src/ccw/launching/LaunchUtils.java

@@ -122,7 +122,7 @@ private static String fileArg(IProject project, IFile file) {
     }
 
     private static IPackageFragmentRoot findPackageFragmentRoot(IJavaProject javaProject, IPath filePath) throws JavaModelException {
-    	if (filePath.isEmpty()) {
+    	if (filePath.isEmpty() || filePath.isRoot()) {
     		return null;
     	} else {
     		IResource possibleFragmentResource = ResourcesPlugin.getWorkspace().getRoot().getFileForLocation(filePath);