This reverts commit 7d6d01b4.

Added FileMailer implementation of mailer interface

Fixes #1162: removed constructors of cache dependency classes so that they can be easily created from configuration.

* 'master' of github.com:yiisoft/yii2:
  Creating transport at 'yii\swiftmailer\Mailer' fixed to track possible "__call".
  Unit test for 'yii\swiftmailer\Message' fixed.

fixes #1161

Proposal for #31: email component based on SwiftMailer

Proposal for accessing populated relations

[ci skip]

Method 'yii\mail\MailerInterface::compose()' reworked allowing rendering message body.