Update active-record.md

add example of using deleteAll
Fixes #3251: controller should be created using DI container.
Cleaning Up
Removed requirements.php reference

Didn’t make any sense, particularly after the browser stuff. If kept,
I’d move it behind the other command-line reference.
More cleaning up
created Appcontroller to make it easiert to debug

controller links application vendor to yiidev repo
refactored Debug Mail panel to work with different vendors

implementation checks for instanceof for additional swiftmailer
capabilities.

issue #2870
Update getting-started.md

Added alternative way of setting up dev environment.
typo in comments

property can be set via [[setComponents()]]
Merge pull request #3255 from lynicidn/patch-1

typo in comments
updated phpdoc
typo
Merge pull request #3257 from pine3ree/patch-1

typo
Merge pull request #3249 from deerawan/master

Update active-record.md
Fixes #3230: Added `yii\filters\AccessControl::user` to support access control with different actors
Edited Introduction

Cut a sentence that seemed both redundant and vague. Could just be me.
Changed Outline

Moved “triggering” after “attaching”.
Edited "attaching event handlers"

Q: When attaching event handlers in the config, does it have to be an
anonymous function?
Edited rest of doc
phpdoc controller did not find some setters

fixes #3255