* expand super types after scanning, for super types that were not scanned. this is helpful in
  * finding the transitive closure without scanning all 3rd party dependencies. it uses {@link
  * ReflectionUtils#getSuperTypes(Class)}.
  * <p>for example, for classes A,B,C where A supertype of B, B supertype of C:
  * <ul>
  *   <li>if scanning C resulted in B (B->C in store), but A was not scanned (although A supertype
  *       of B) - then getSubTypes(A) will not return C
  *   <li>if expanding supertypes, B will be expanded with A (A->B in store) - then getSubTypes(A)
  *       will return C
  * </ul>
 public void expandSuperTypes() {
   if (store.keySet().contains(index(SubTypesScanner.class))) {
     Multimap<String, String> mmap = store.get(index(SubTypesScanner.class));
     Sets.SetView<String> keys = Sets.difference(mmap.keySet(), Sets.newHashSet(mmap.values()));
     Multimap<String, String> expand = HashMultimap.create();
     for (String key : keys) {
       expandSupertypes(expand, key, forName(key));