[apps] Create an abstract class of data model and of data controller

Change-Id: I764b07bde5f81068eaeebed80969f410495bf6b6

apps/data.cpp

@@ -0,0 +1,9 @@
+#include "data.h"
+
+Data::Data() :
+  m_numberOfPairs(0)
+{
+}
+int Data::numberOfPairs() {
+  return m_numberOfPairs;
+}