add sorting icons to gridview sort links in basic and advanced app css
minor code refacotring.
Fixes #1075: changed the default value of GridView::empty.
Fixes issue #1078: Typo in comment
Merge pull request #1079 from nukkumatti/master

Fixes issue #1078: Typo in comment
typo fix.
Update FallbackMessageFormatter.php

Fix declarations for yii\i18n\FallbackMessageFormatter::format() and yii\i18n\FallbackMessageFormatter::formatMessage()
Merge pull request #1083 from rosko/master

Update FallbackMessageFormatter.php
Merge remote-tracking branch 'upstream/master' into self

* upstream/master:
  Update FallbackMessageFormatter.php
  typo fix.
  Fixes issue #1078: Typo in comment
  Fixes #1075: changed the default value of GridView::empty.
  minor code refacotring.
  add sorting icons to gridview sort links in basic and advanced app css