Added am:app service stub.

Apparently nothing at all is known about this service...

src/core/hle/service/am_app.cpp

@@ -0,0 +1,23 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include "common/log.h"
+#include "core/hle/hle.h"
+#include "core/hle/service/am_app.h"
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// Namespace AM_APP
+
+namespace AM_APP {
+
+const Interface::FunctionInfo FunctionTable[] = {
+};
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// Interface class
+
+Interface::Interface() {
+    Register(FunctionTable, ARRAY_SIZE(FunctionTable));
+}
+
+} // namespace