Use autotls instead of multitls in websocket:
The MultiSocket class implements a socket that handshakes in multiple
protocols including SSL and PROXY. Unfortunately the way it type-erases the
handlers and buffers is incompatible with boost::asio coroutines. To pave the
way for coroutines this is part of a larger set of changes that roll back the
usage of MultiSocket to older code, and some custom implementations that use
templates. The custom implementations are more simple since they use
coroutines. Removing MultiSocket will make many other classes and source files
unused, a big win for trimming down the codebase size.
Workaround for MSVC stdlib and coroutine interaction:
If beast::Time::currentTimeMillis is first called from a coroutine launched
using boost::asio::spawn, Win32 throws an exception. This workaround calls
getCurrentTime once in main to prevent the exception.
Reference:
    https://svn.boost.org/trac/boost/ticket/10657
Add beast::asio::ssl_bundle workaround:
This works around the limitation that 1.56 boost::asio::ssl::stream objects
do not support r-value move or construction. It is required when the stream
does not own the socket.
Return error_code from beast::http::basic_parser:
This changes the HTTP parser interface to return an error_code instead
of a bool. This eliminates the need for the error() member function and
simplifies calling code.
Keep a list of section config values that are not key/value pairs:
This change to BasicConfig stores all appended lines which are not key/value
pairs in a separate values vector which can be retrieved later. This is to
support sections containing both key/value pairs and a list of values.
Remove HTTP::ScopedStream:
This class was used to allow stream style operator<< to write to the
HTTP::Session. This is being superceded by a more robust object-based model
that supports coroutines.