fixed several issues with apidoc generator
Merge pull request #2471 from yiisoft/markdown

Changed markdown library to cebe/markdown
env. config fixed
visibility fix
added test-case to frontend unit tests
Merge pull request #2478 from Ragazzo/yii2_advanced_tests_fixed

Yii2 advanced tests fixed
test typo fix
Merge pull request #2479 from Ragazzo/yii2_advanced_tests_typo

test typo fix
mongodb method "open" not triggered event "after open connection"
add method findOne() to the Collection class
small typos
refactoring Session component
removed useless option
Fixes #2415: Added support for inverse relations
Update active-record.md

typo
Merge pull request #2480 from mongosoft/mongodb

Mongodb extension refactorign
Fixes #2490: `yii\db\Query::count()` and other query scalar methods now properly handle queries with GROUP BY clause
Fix scrollbar in the Debug module when viewing PHP info output
Merge pull request #2494 from resurtm/fix-debug-scroll-bar

Fix scrollbar in the Debug module when viewing PHP info output
added tests for smarty and worked around a small bug

fixes #2265