Add combined memory and swap meter

Closes: #699

openbsd/Platform.c

@@ -32,6 +32,7 @@ in the source distribution for its full text.
 #include "LoadAverageMeter.h"
 #include "Macros.h"
 #include "MemoryMeter.h"
+#include "MemorySwapMeter.h"
 #include "Meter.h"
 #include "ProcessList.h"
 #include "Settings.h"
@@ -98,6 +99,7 @@ const MeterClass* const Platform_meterTypes[] = {
    &LoadMeter_class,
    &MemoryMeter_class,
    &SwapMeter_class,
+   &MemorySwapMeter_class,
    &TasksMeter_class,
    &UptimeMeter_class,
    &BatteryMeter_class,