5.0.0

• Removed Claims class (deprecated since 1.0)
• Removed getClaims and setClaims methods from Entity, Item and Property (deprecated since 1.0)
• Removed HashableObjectStorage class (deprecated since 4.4)
• ReferenceList no longer derives from SplObjectStorage
  • Removed addAll, attach, contains, detach, getHash, getInfo, removeAll,
    removeAllExcept and setInfo methods
• ReferenceList no longer implements ArrayAccess
  • Removed offsetExists, offsetGet, offsetSet and offsetUnset methods
• ReferenceList no longer implements Iterator
  • Removed current, key, next, rewind and valid methods
• ReferenceList now implements IteratorAggregate
  • Added getIterator method
• Removed ReferenceList::removeDuplicates
• ReferenceList::addReference now throws an InvalidArgumentException for negative indices
• Added EntityDocument::equals, and EntityDocument now implements Comparable
• Added EntityDocument::copy
• Fixed Property::clear not clearing statements
• TermList now skips and removes empty terms
• Deprecated ByPropertyIdArray