added option for hiding any app from Settings Manager by adding 'X-UBL-SettingsManager-Hidden=true' (absence of that string means false) in its .desktop file

source/ubl-settings-manager.c

@@ -877,6 +877,7 @@ apps *find_apps(int *sizef){
                         tempapp.Pluggable=g_key_file_get_boolean(gfile,"Desktop Entry", "Pluggable",NULL);
                         if (!tempapp.Pluggable) tempapp.Pluggable=g_key_file_get_boolean(gfile,"Desktop Entry", "X-XfcePluggable",NULL);
                         if (tempapp.Pluggable) tempapp.DualPluggable=g_key_file_get_boolean(gfile,"Desktop Entry", "X-UBLPluggable",NULL);
+                        if (g_key_file_get_boolean(gfile,"Desktop Entry", "X-UBL-SettingsManager-Hidden",NULL)==1)
                             if (size==0){
                                 applist=(apps*)malloc(size+1*sizeof(apps));
                                 applist[0].Name=yon_char_new(tempapp.Name);