breaking changes.

To comply with the docs RE namespace usage:
https://github.com/yiisoft/yii2/blob/master/docs/guide/extend-creating-extensions.md

fixes #3289

do not allow empty property name
fixes #3297

Adding a new additional validation rule in the gii-crud generator enforcing the expected format.

implementation checks for instanceof for additional swiftmailer
capabilities.

issue #2870

removed unused code $patterns

useTablePefix => useTablePrefix

use tableprefix on gii model generator

typo fix

Fixes #1263: Fixed the issue that Gii and Debug modules might be affected by incompatible asset manager configuration