Configuration driven ignored user agents and exceptions are completely ignored

Commit 2a34eaeb80106269eba3a376129ac26a85ca4682 refactored the user-agent and exception sniffing code but did not take into account the ability to configure these settings from `exceptional.yml`:

https://github.com/exceptional/exceptional/blob/0381b29bf1e6d0376e38ff9d48536104698640f4/lib/exceptional/config.rb#L54-L55

i.e. `ignored_agents` and `ignored_exceptions` **!=** `ignore_user_agents` and `ignore_exceptions`.