Clear macros on shutdown

This was done implicitly in the shutdown handler by clearing the
plugin's settings.
Due to unwanted side effects this behavior has been disabled for the
shutdown and thus macros have to be cleared explicitly on shutdown.

lib/macro/macro.cpp

@@ -17,6 +17,17 @@
 
 namespace advss {
 
+static bool setup()
+{
+	AddPluginCleanupStep([]() {
+		GetTopLevelMacros().clear();
+		GetTemporaryMacros().clear();
+	});
+	return true;
+}
+
+static bool setupDone = setup();
+
 Macro::Macro(const std::string &name) : _dockSettings(this)
 {
 	SetName(name);