restructure and add server/client example

app/inc/sys.hpp

@@ -0,0 +1,9 @@
+
+
+namespace sys
+{
+  const char *transformFilePath(const char *filename);
+  size_t saveDataToFile(const char *filename, void *data, size_t size);
+  size_t loadDataFromFile(const char *filename, void *data, size_t size);
+  bool fileExists(const char *filename);
+}