add BOOST_ASIO_MOVE_ARG for Handler.

Signed-off-by: Jack <jack.wgm@gmail.com>
add AVHTTP_*_HANDLER_CHECK for avhttp.

Signed-off-by: Jack <jack.wgm@gmail.com>
Merge branch 'master' of github.com:avplayer/avhttp

Conflicts:
	include/avhttp/impl/http_stream.ipp

Signed-off-by: Jack <jack.wgm@gmail.com>