metrics: set of metrics (in the form of boost::variant with metric index enum) analogous to internal_metric has been added.
json_dump: dump_timestamp renamed to json_dump_timestamp.
json_dump: HANDY_JSON_DUMP() return const shared_ptr now to forbid user to modify shared_ptr.
metrics_dump: metrics dump has been added. This dump is similar to json dump but is in form of std::map data structure with const metrics.
const_metrics: const metrics are used in metrics_dump and are nothing else but just metrics with const modifier.
configuration: special section for metrics dump has been added (analogous to json dump).
json_dump: zero json dump interval configuration disables json dump creation.
metrics_dump: zero metrics dump interval configuration disables metrics dump creation.