Moved most components of the library to iterators:: namespace.

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.

include/boost/generator_iterator.hpp

@@ -17,6 +17,7 @@
 #include <boost/ref.hpp>
 
 namespace boost {
+namespace iterators {
 
 template<class Generator>
 class generator_iterator
@@ -33,7 +34,7 @@ class generator_iterator
       , single_pass_traversal_tag
       , typename Generator::result_type const&
     > super_t;
-    
+
  public:
     generator_iterator() {}
     generator_iterator(Generator* g) : m_g(g), m_value((*m_g)()) {}
@@ -73,8 +74,12 @@ make_generator_iterator(Generator & gen)
   return result_t(&gen);
 }
 
+} // namespace iterators
+
+using iterators::generator_iterator;
+using iterators::generator_iterator_generator;
+using iterators::make_generator_iterator;
+
 } // namespace boost
 
-
 #endif // BOOST_ITERATOR_ADAPTOR_GENERATOR_ITERATOR_HPP
-