AndFilter and OrFilter have broken equals() and hashCode() contract

[rolfl]

OrFilter and AndFilter should not break hashCode() and equals() contract.

For example:

ElementFilter efa = new ElementFilter("a");
ElementFilter efb = new ElementFilter("b");

OrFilter orfa = efa.or(efb);
OrFilter orfb = efb.or(efa);

// the following succeeds
assertTrue(orfa.equals(orfb));
// the following fails.
assertTrue(orfa.hashCode() == orfb.hashCode());

Re-Enable JUnit tests in AbstractTestFilter once fixed.