unnecessary boost/bind.hpp deprecation warnings

Quite a few boost libraries still "#include " 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 " 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 .