Roll message dispatching mechanism back to 1.2 (because atomic object is more efficient than strand).
Rename macro ASCS_RECV_AFTER_HANDLING to ASCS_PASSIVE_RECV.
Guarantee only one or zero async_read invocation even if macro ASCS_PASSIVE_RECV been defined.
Fix bug: even defined macro ASCS_RECV_AFTER_HANDLING, udp::socket may still initiate async_read automatically.

1. Stack overflow may occur when dispatching message;
2. The last message may left behind in the receiving buffer.

Class object has been split into executor and tracked_executor, object_pool use the former, and ascs::socket use the latter.

Tidy ascs::object.

Fix: Reconnectiong may happen in ascs::socket::reset, it's not a right behavior.
Do reconnecting in client_socket_base::after_close rather in client_socket_base::on_close.

Fix:
Support unmovable buffers (for example: a very short std::string).
begin_time not inherited while accessing concurrent queue.
Eliminate race condition in udp::socket_base.
Eliminate race condition in demo file_client.
Avoid division by zero error in demo file_client.

Support decreasing the number of service thread at runtime.
Not support Visual C++ 11.0 (2012) any more, use st_asio_wrapper instead.
Optimized and simplified auto_buffer, shared_buffer and ext::basic_buffer.
Optimized class obj_with_begin_time.
Not use sending buffer (send_msg_buffer) if possible.
Reduced stopped() invocation (because it needs locks).
Introduced asio::io_service::work (asio::executor_work_guard).
i_server has been moved from ascs to ascs::tcp.
Move all deprecated classes (connector_base, client_base, service_base) to alias.h
Rename tcp::client_base to tcp::multi_client_base, ext::tcp::client to ext::tcp::multi_client, udp::service_base to udp::multi_service_base,
 ext::udp::service to ext::udp::multi_service. Old ones are still available, but have became alias.

Support unstripped message.
Add two demos for concurrent test.
define ASIO_NO_DEPRECATED macro by default in VC++ projects.
Truly support asio 1.11 (don't use deprecated functions and classes any more), and of course, asio 1.10 will be supported too.
Use mutable_buffer and const_buffer instead of mutable_buffers_1 and const_buffers_1 if possible.