Fix deprecated usage of boost/bind.hpp.

boost/bind.hpp emits compiler warnings about deprecation of the header
and global _N placeholders. This commit converts usage of this header
to boost/bind/bind.hpp and using namespace boost::placeholders.

Where boost::bind is not actually used, the includes are removed.

test/algorithm_test/unique.cpp

@@ -15,7 +15,6 @@
 #include <boost/test/unit_test.hpp>
 
 #include <boost/assign.hpp>
-#include <boost/bind.hpp>
 #include <boost/config.hpp>
 #include "../test_driver/range_overload_test_driver.hpp"
 #include <algorithm>