add cpp-lib example; some fixes

cpp-lib/cpp/lib.cpp

@@ -0,0 +1,27 @@
+#include "lib.h"
+#include <QtDebug>
+
+QT_BEGIN_NAMESPACE
+
+QObject* ini() {
+  // any QObject inherited class will do
+  static QObject* cpp = 0;
+  if(!cpp) {
+    cpp = new CPP;
+  }
+  return cpp;
+}
+
+// insert here your function implementations
+
+QVariant CPP::hello(const QVariant& arg) {
+  QString msg;
+  QDebug debug(&msg);
+  debug << arg;
+
+  qDebug() << "hello" << arg;
+
+  return arg;
+}
+
+QT_END_NAMESPACE