C++ named requirements: AssociativeContainer

An AssociativeContainer is an ordered Container that provides fast lookup of objects based on keys.

# Defect reports

DRApplied toBehavior as publishedCorrect behavior
LWG 354C++98lower_bound and upper_bound did notreturn the end iterator if no element is foundthey return the enditerator in this case
LWG 589C++98the elements that i and j referto had the type X::value_typethe elements are implicitlyconvertible to X::value_type