Removed error-block HTML class and related styles and used Bootstrap3 standard practice about errors instead

Add pt-BR translated messages

Fixes #1633: fixed scenarios for User model in advanced application allowing setting default values for User model

Advanced app template: moved database connection DSN, login and password to -local config not to expose it to VCS

fixes #1821

Fixes #1835: `CheckboxColumn` now renders checkboxes whose values are the corresponding data key values

Fixes #1827: Debugger toolbar is loaded twice if an action is calling `run()` to execute another action

Changed Yii autoloader to support loading PSR-4 classes only (i.e. PEAR-styled classes not supported anymore)

Doc fixes

Typo fix