Upgrade to commons-collections 4.1

** Sub-task
    * [COLLECTIONS-464] - Add FluentIterator / FluentIterable implementation
    * [COLLECTIONS-572] - Create real set operations for SetUtils

** Bug
    * [COLLECTIONS-426] - performance problem in ListOrderedSet.retainAll()
    * [COLLECTIONS-427] - performance problem in SetUniqueList.retainAll()
    * [COLLECTIONS-506] - Result of CollectionUtils are different between version 3.2.1 and version 4.0
    * [COLLECTIONS-507] - ComparatorUtils.chainedComparator(..) should not force the objects to implement Comparable
    * [COLLECTIONS-509] - Clarify javadoc of CollectionBag
    * [COLLECTIONS-512] - equals/hashCode mismatch
    * [COLLECTIONS-516] - NullPointerException in MapUtils.toProperties
    * [COLLECTIONS-521] - Typo in MultiMapKey's isEqualKey(entry, key1, key2)
    * [COLLECTIONS-524] - ListOrderedSet can have duplicates
    * [COLLECTIONS-525] - PatriciaTrie
    * [COLLECTIONS-531] - Generic Wildcards specified in CollectionUtils#isEqualCollection(Collection, Collection, Equator) may throw ClassCastException in certain cases
    * [COLLECTIONS-534] - Performance bug in CollectionBag::retainAll
    * [COLLECTIONS-536] - (Code style) map.size() call in MapUtils.putAll()
    * [COLLECTIONS-537] - PredicateUtils (all|any)Predicate type misbehaviour Array vs. Collection
    * [COLLECTIONS-543] - AbstractCollectionDecorator should not delegate equals and hashcode
    * [COLLECTIONS-544] - Undocumented performance issue in the retainAll method in CollectionUtils 
    * [COLLECTIONS-545] - Undocumented performance issue in the removeAll method in CollectionUtils
    * [COLLECTIONS-553] - TransformedMultiValuedMap.equals() fails when comparing the value with itself
    * [COLLECTIONS-555] - Undefined NullPointerException in TreeBag.java
    * [COLLECTIONS-558] - ListOrderedSet#remove(int) should return E instead of Object
    * [COLLECTIONS-566] - IteratorUtils.collatedIterator do not use natural ordering if no comparator was provided
    * [COLLECTIONS-570] - All decorators shall throw a NullPointerException if the decorated argument is null
    * [COLLECTIONS-576] - MultiKey subclassing has deserialization problem since COLLECTIONS-266: either declare protected readResolve() or MultiKey must be final
    * [COLLECTIONS-577] - PatriciaTrie bugs when only a few bits change
    * [COLLECTIONS-580] - Arbitrary remote code execution with InvokerTransformer

** Improvement
    * [COLLECTIONS-442] - A set of enhanced iterator classes donated by the Apache Jena project
    * [COLLECTIONS-508] - MultiMap's methods are not strongly typed even though the interface supports generics
    * [COLLECTIONS-510] - ReverseComparator does not compile under Java 8
    * [COLLECTIONS-522] - Documentation example does not compile
    * [COLLECTIONS-523] - Removing unnecessary method
    * [COLLECTIONS-529] - Add removeAll(Collection<E> collection, Collection<E> remove, Comparator<E> comparator) and contains(Collection<E> collection, E object, Comparator<E> comparator) methods
    * [COLLECTIONS-530] - Rejecting items on predicate failure without throwing an Exception
    * [COLLECTIONS-539] - CircularFifoQueue: make 'isAtFullCapacity' method public
    * [COLLECTIONS-540] - Duplication of code in CollectionUtils
    * [COLLECTIONS-551] - Move Iterable related methods from CollectionUtils to IterableUtils
    * [COLLECTIONS-557] - LRUMap memory usage vs size

** New Feature
    * [COLLECTIONS-471] - Add a BoundedIterator which returns at most limit elements
    * [COLLECTIONS-503] - IfTransformer
    * [COLLECTIONS-511] - CollectionUtils.bisect(...), this would be a combination of Select and SelectRejected
    * [COLLECTIONS-550] - Provide a simple way for creating an arbitrary String representation of a given Iterable
    * [COLLECTIONS-556] - Add an IdentityHashSet
    * [COLLECTIONS-565] - Add support for NavigableSet interface
    * [COLLECTIONS-567] - Add a MultiSet interface / implementations that do not violate the Collection contract

** Task
    * [COLLECTIONS-542] - AbstractHashedMap should not extend AbstractMap anymore
    * [COLLECTIONS-562] - Update minimum required java to 1.6
    * [COLLECTIONS-571] - Deprecate CollectionUtils.{synchronized, unmodifiable}Collection methods

** Wish
    * [COLLECTIONS-395] - Request for UnBoundedLRUMap implementation with extra get method