Use toggle Buttons for MIME sign and encrypt
* src/gpgoladdin.cpp (GpgolRibbonExtender::GetCustomUI): Use toggle buttons. (GpgolRibbonExtender::Invoke): Toggle button param 0 is the state. 1 the dispatch interface. * src/ribbon-callbacks.cpp (message_flag_status): Removed. (mark_mime_action): Don't use flag status.