code: protected void gatherSources(Collection<String> templateNames,
                                   File sourceDir, boolean recurse)
          throws IOException {
          gatherSources(templateNames, sourceDir, null, recurse);
      }
docs: Gathers all sources (template names) in the source directory.
  
  @param templateNames Collection of Strings. The gatherSources method
  will add the template names to this Collection.
  @param sourceDir the root source directory
  @param recurse When true, recursively gathers all sources in
  sub-directories.