Rename udp::multi_service_base to multi_socket_service_base.
Rename ext::udp::single_service to single_socket_service.
Rename ext::udp::multi_service to multi_socket_service.
Rename ext::udp::service to socket_service.

Drop the 'reset' parameter in multi_socket_service::add_socket, this means never call reset() for the socket anymore.
Don't call reset() in ascs::single_socket_service::init() and ascs::multi_socket_service::init() anymore.

Fix bug: queue::size_in_byte() may return wrong data with macro ASCS_SYNC_RECV or ASCS_SYNC_DISPATCH.

Fix infinite waiting after sync message sending or receiving failed.

Rename replaceable_unpacker to unpacker2, replaceable_udp_unpacker to udp_unpacker2, replaceable_packer to packer2,
 because their names confuse users, any packer or unpacker is replaceable for those packer or unpacker that has the same msg_type.

Return the concept of 'size' and 'empty' in class queue to the Container's, and introduce new concept 'size_in_byte' to represent the memory size occupied by the queue.

Make force_shutdown and graceful_shutdown be able to reconnect the server even if the link has broken.

Export some typedefs in container to class queue.

Optimize class queue.

Explicitly require the first parameter to be rvalue reference for i_packer::pack_msg(container_type&&, container_type&).