project: added project skeleton

Skeleton includes emtpy implementations of application class structure.
Source groups were added to CMakeLists to define filters in Visual Studio.

src/lib/data/ElementIndex.h

@@ -0,0 +1,9 @@
+#ifndef ELEMENT_INDEX_H
+#define ELEMENT_INDEX_H
+
+class ElementIndex
+{
+};
+
+
+#endif // ELEMENT_INDEX_H