Updated net/nagstamon to version 0.9.9

Upstream changes:
-----------------

    added custom actions in context menu (see documentation)
    added reauthentication in case of authenticaton problems
    added filter for flapping hosts and services
    added history button for monitors
    added shortcut to filter settings in popup window
    improved keyboard usage in acknowledge/downtime/submit dialogs
    changed configuration file to configuration directory (default: ~/.nagstamon)
    fixed bug in Icinga acknowledgement
    fixed bug in Check_MK Multisite sorting
    fixed some Check_MK Multisite UTF trouble
    fixed some major GUI bugs

(gls)