Add 'used' parameter to memory-windows ITL command

doc/10-icinga-template-library.md

@@ -1546,6 +1546,7 @@ Name              | Description
 memory\_win\_warn | **Optional**. The warning threshold. Defaults to "10%".
 memory\_win\_crit | **Optional**. The critical threshold. Defaults to "5%".
 memory\_win\_unit | **Optional**. The unit to display the received value in, thresholds are interpreted in this unit. Defaults to "mb" (megabyte), possible values are: b, kb, mb, gb and tb.
+memory\_win\_show\_used | **Optional**. Show used memory instead of the free memory.
 
 
 ### network-windows <a id="windows-plugins-network-windows"></a>

itl/command-plugins-windows.conf

@@ -85,6 +85,10 @@ object CheckCommand "memory-windows" {
 			value = "$memory_win_unit$"
 			description = "Use this unit to display memory"
 		}
+		"-U" = {
+                        set_if = "$memory_win_show_used$"
+                        description = "Show used memory instead of the free memory"
+                }
 	}
 
 	//The default