Immediate completions in connection and any_connection are now correctly
dispatched to the token's immediate executor using asio::async_immediate
instead of plain asio::post.
Added a section on executors in the reference docs of async functions in
connection and any_connection
Disabled TSAN connection_pool_cancel_get_connection for libc++ builds
close#301
Thread-safety is now achieved using pool_params::thread_safe.
Removed pool_executor_params::thread_safe
Unsafe pools now use the standard Asio semantics
Safe pools are now safe even if the handlers' associated executors point
to a context different from the pool's context
close#268
Separate compilation
Immediate completions are now posted through the I/O executor
Jamfiles now correctly requires C++11
Refactored the protocol and channel modules
Removed example on default completion tokens
close#23close#112
