Get the wrappers working with SWIG 4.0 (#5795)

* extend the allowed valences of the alkali earths
make it possible to have preferred and arbitrary valence states (I thought this already worked)

* backup

* maybe needed

* copy in some swig3 files;
at this point the tests all work

* remove SWIG version lock

* changes in response to review

Code/JavaWrappers/ExplicitBitVect.i

@@ -65,7 +65,7 @@
      UChar_Vect vec = new UChar_Vect();
      vec.reserve(fp.length);
      for (int size=0;size<fp.length;++size) {
-       vec.add(fp[size]);
+       vec.add((short)fp[size]);
      }
      return new ExplicitBitVect(vec);
    }