Upgrade to commons-collections 4.3

** Bug
    * [COLLECTIONS-689] - Link to Javadoc API broken
    * [COLLECTIONS-701] - StackOverflowError in SetUniqueList.add() when it receives itself
    * [COLLECTIONS-709] - MultiSet.Entry::getCount() isn't 0 after removing the last element

** New Feature
    * [COLLECTIONS-692] - Replace use of deprecated Class#newInstance() #49
    * [COLLECTIONS-706] - Add SetUtils.unmodifiableSet(T... items) method

** Improvement
    * [COLLECTIONS-551] - Move Iterable related methods from CollectionUtils to IterableUtils
    * [COLLECTIONS-688] - Update platform requirement from Java 7 to 8
    * [COLLECTIONS-691] - Use boolean operator for boolean result
    * [COLLECTIONS-696] - AbstractReferenceMap made easier for subclassing; PR #51.
    * [COLLECTIONS-703] - The PassiveExpiringMap#put() method should return the previous record only if not expired

** Task
    * [COLLECTIONS-542] - AbstractHashedMap should not extend AbstractMap anymore