This should silence gcc warnings about deprecated implicit copy assignment
operator because of the explicitly defined copy constructor. Also, changed
constructor definitions to be defaulted when possible and added missing
includes.
Closes https://github.com/boostorg/iterator/pull/69.
This change excludes boost:: and boost::detail:: namespaces from ADL for unqualified function calls (e.g. algorithms). This reduces the possibility of name clashes with other libraries and user's code. One of the effects should be fixing test failures on gcc 4.2 and 4.4 due to clashed with Boost.TypeTraits.
Also some of the functions marked with inline keyword.