add xml file support

[zork]

Allow to serialize store tables to and from xml files in similar way that csv file handling. XML serialization format should be able to:

• create and read xml files and fill object members from it including BIND_COL and BIND_CLA macros (serialization of aggregated objects)
• optionally update existing xml file if object identifiers are stored in it
• allow to configure XMLArchive to write object members as xml attributes or xml nodes. This configuration should be configurable at serialization time - object member can be stored either as attribute or as node depending on object context, object value or other conditions.