Fix logging of array messages.
Fix logging of array messages.

Log messages can be either strings or arrays in Yii.
If a message is not a string, log it with VarDumper::export,
like other Yii log targets.
Additionally, send it to Sentry as an array in 'extra',
so that it can be displayed nicely.

Fixes #9

hellowearemito/yii2-sentry,hellowearemito/yii2-sentry