Systray: option to configure monitor (fixes issue 451 and TODOs in the code)

git-svn-id: http://tint2.googlecode.com/svn/trunk@667 121b4492-b84c-0410-8b4c-0d4edfb3f3cc

src/config.c

@@ -563,6 +563,9 @@ void add_entry (char *key, char *value)
 		systray.saturation = atoi(value2);
 		systray.brightness = atoi(value3);
 	}
+	else if (strcmp(key, "systray_monitor") == 0) {
+		systray_monitor = atoi(value);
+	}
 
 	/* Launcher */
 	else if (strcmp (key, "launcher_padding") == 0) {