Added BaseChannelSecurableInterface.
BaseChannel: close() method extracted from Adaptee::close().

Connection type changed from QueuedConnection to DirectConnection,
because close() method will be used in destructor.
BaseConnection: Channels now will be closed on obj destruction.
BaseConnection: Implemented RequestsInterface::channelClosed() emission.
BaseConnection::Adaptee: Fixed getProtocol().
Added BaseChannelChatStateInterface.