v.5.8.2

This is a small update that introduces a few tiny features and fixes some flaws.

An optional name can be specified for an agent (#76).

There is another constructor for so_5::wrapped_env_t that waits completion of the init-function (#74).

New as_string_view methods for so_5::stats::prefix_t and so_5::stats::suffix_t classes.

A new type of subscription storage and new factory so_5::flat_set_based_subscription_storage_factory().

A possibility to set default "global" subscription storage factory via new method so_5::environment_params_t::default_subscription_storage_factory().

More detailed descriptions of new features can be found on the corresponding Wiki page.