Improved "count" for unique associative containers. Instead of calling tree's count just use find() != end() to avoid iterations as there is only one potential key.

Fixed some typos.

include/boost/intrusive/treap_algorithms.hpp

@@ -248,6 +248,7 @@ class treap_algorithms
    //! @copydoc ::boost::intrusive::bstree_algorithms::count(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
    template<class KeyType, class KeyNodePtrCompare>
    static std::size_t count(const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp);
+
    #endif   //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
 
    //! <b>Requires</b>: "h" must be the header node of a tree.