Raw content return for Grid DataColumn & Column

Need to have a method  `getDataCellContent` to return raw parsed data cell content. This is useful when extending these Columns, for processing any other data before formatting via `renderDataCellContent`.
Raw content return for Grid DataColumn & Column

Need to have a method  `getDataCellContent` to return raw parsed data cell content. This is useful when extending these Columns, for processing any other data before formatting via `renderDataCellContent`.
Raw content return for Grid DataColumn & Column
Raw content return for Grid DataColumn & Column
Removed unnecessary blank space
Removed unnecessary blank space
first draft of the extension generator
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
Fixes #2360: Added `AttributeBehavior` and `BlameableBehavior`, and renamed `AutoTimestamp` to `TimestampBehavior`