mandos-monitor: New "verbose" mode to see less important log messages.
* mandos-monitor (MandosClientWidget.__init__): Log client creation. (MandosClientWidget.checker_completed): Log a successful checker. (MandosClientWidget.checker_started): Log starting of a checker. (UserInterface.__init__): New optional "log_level" argument. (UserInterface.log_message, UserInterface.log_message_raw): Take optional "level" arg. (UserInterface.toggle_log_display): Log visibility change. (UserInterface.change_log_display): Log wrap mode change. (UserInterface.process_input): Show new "v" key in help message and process "v" key if pressed. * mandos-monitor.xml (KEYS): Document new "v" key.