Typo fix
Merge pull request #1829 from munawer-t/master

Typo fix
Typos
SwiftMailer message updated to setup charset for alternative body correctly.
Issue #1817 added to CHANGELOG
Merge branch 'master' of github.com:yiisoft/yii2
PhpDoc fixes
Merge pull request #1832 from munawer-t/master

Doc fixes
Changed Yii autoloader to support loading PSR-4 classes only (i.e. PEAR-styled classes not supported anymore)
Added support for installing packages conforming to PSR-4 standard
Fixes #1827: Debugger toolbar is loaded twice if an action is calling `run()` to execute another action
Fixes #1835: `CheckboxColumn` now renders checkboxes whose values are the corresponding data key values
updated extension changelog.
UplodedFile enhasement
default values for db\Connection username and password to null

fixes #1821
UplodedFile enhasement
UplodedFile enhasement
UplodedFile enhasement
Advanced app template: moved database connection DSN, login and password to -local config not to expose it to VCS
Adjusted advanced application template docs to reflect DB config movement