We need to extract current mail agent implementation to separated repository, like drivers in Mink.

Resulted package list may be like this: staffim/behat-mail-extension, staffim/behat-mail-ezc-agent.

Define parameters with simple :argument notation, not with regular expressions. We don't need them in most places.

I suggest do some model refactoring.

By steps:

1. Introduce MailAgentInterface and default ezcomponents/mail implementation. This interface will contain all actions on mails (sending, removing, receiving). This interface represents mail agent from a real life, like mutt and Outlook.
2. Refactor Mailbox and Mail classes to be abstract data containers (Mailbox will be simple collection of Mail objects with some specific methods).

Most (all, I think) checking tasks can be wrapped to waiting loop. This will be extremely useful, no more handwritten waiting steps.

Add ability to save raw mail message in file after failed mail scenario