added note about usage to AR::instantiate()

fixes #2370
improved config
Merge pull request #2389 from Ragazzo/basic_app_mail_config

improved config
Renamed csrfParam back to csrfVar for consistency.
fixed path traversal
yii\mongodb\Collection::mapReduce() fixed to handle 'inline' output correctly.
view improved
added check for file name
fixed message
Merge pull request #2394 from Ragazzo/mail_view

view improved
adjusted wording.
Very minor edits
spaces to tabs
applied coding standards
added h1 for request panel
added check for db and request panel, disabled output if one is missing
Merge commit 'b2a2853eabbd5d91cf4772dd0dbd4c3003e61e33' into feature/toolbar-ui-3
Fixes #2399: Fixed the bug that AssetBundle did not handle relative URLs correctly
Merge pull request #2401 from schmunk42/feature/toolbar-ui-3

Feature/toolbar ui 3
Fixed test break.