Show specific error message when subject not found.

Merge pull request #89 from systemovich/more_collection_backwards_com…

…patibility

Make InteractsWithMail::getMessagesFor compatible with Laravel 5.2

Fix mailer memoization to work without tap

Merge pull request #82 from tightenco/memoize-mailer

Memoize mailer.

Merge pull request #80 from wells/bugfix-laravel-5-5

[Bugfix] Update InteractsWithMail to account for older versions of phpunit

Make MailThief compatible with Laravel 5.5

Prevent laravel 5.5 from breaking queue contract

Make NullMessageForView respond with a string for embed methods

Merge pull request #70 from exls/master

Fix: trait method seeMessageFrom should work when from set with name

Merge pull request #69 from alepeino/getter

Call mailer getter in seeInSubjects