unnecessary boost/bind.hpp deprecation warnings

[bitbugprime]

Quite a few boost libraries still "#include <boost/bind.hpp>" and use _1, _2, etc without their boost::placeholders scope prefix. This generates unnecessary deprecation warnings in user code, not to mention boost itself.

They should instead "#include <boost/bind/bind.hpp>" and replace all uses of naked _1, _2, etc with boost::placeholders::_1, boost::placeholders::_2, etc.

Affected libraries: algorithm bind gil graph iostreams log msm multi_index numeric property_map property_tree python signals2 statechart test thread variant

Numerous additional tests and code examples also use <boost/bind.hpp>.