far better than depending on fat guzzle

fixes #1319

Model::attributes() has been made static

as suggested in issue #1316

fixes #1316

[ci skip]

"yii\sphinx\ActiveQuery" updated to throw exception on conflict between "asArray" and "snippetByModel" options.

yii\sphinx\DataReader removed.

Removed edited author ref.

Updated tabs

Corrected the example and doc to highlight allowed dropdown support in Bootstrap 3.

fixes #1284

"yii\swiftmailer\Mailer" transport setup has been advanced to support constructor arguments and plugins.