fix#773
* buffer_prefix is renamed to buffers_prefix
* buffer_prefix_view is renamed to buffers_prefix_view
Actions Required:
* Use buffers_prefix instead of buffer_prefix
* Use buffers_prefix_view instead of buffer_prefix_view
fix#642
This changes websocket::stream close and async_close to automatically
read and discard incoming message frames before shutting down the
connection. It is no longer necessary to manually drain the connection.
fix#575, fix#604, fix#608, fix#634, fix#712
All examples are rewritten:
* Using Best Practices
* Mostly self-contained
* New examples to complete the feature matrix
* The server-framework example is removed
fix#642
* Calls to stream::close and stream::async_close will
automatically perform the required read operations
Actions Required:
* Remove calling code which drains the connection after
calling stream::close or stream::async_close
