updated extension documentation

updated database, based on @cebe's comment https://github.com/yiisoft/yii2/pull/1485#discussion_r8410809

fixes #1560

make Query reuseable

fixes #1545

fixed #1021

fixes #1545

fixes #1553

fixes #1556

fixes #1474

issue #1523

follow up to PR #1393

Merge PR #1393 branch 'yii2-basic-codeception' of https://github.com/Ragazzo/yii2 into Ragazzo-yii2-basic-codeception

* 'yii2-basic-codeception' of https://github.com/Ragazzo/yii2:
  small typo fix
  added readme, changelog, license and composer files.
  added new extension yii2-codeception, modified composer settings
  modified tests according yii2-codeception extension
  added testcase for unit tests, bootstrap files improved, tests inherited from base testcase
  configs fixed and improved
  tests modified, bootstrap added
  colors added
  new entry points for application
  codeception configs, web config modifed for db-settings

Conflicts:
	composer.json

Allow multiple navbars

Changed the navbar target to be based of the widget id and not static.

fixes #1541