change usual code style to php code style

Fixes #497: Removed `\yii\log\Target::logUser` and added `\yii\log\Target::prefix` to support customizing message prefix

fix GridView filterUrl bug

GII generated files changes according to PSR2

- readded removed file
- readded use statement to migration template

typo fix in gii.md

Fixed typo in FilterValidator for skipping array values.

Reformat code to be PSR-2 compatible

Fixes #2729: Added `FilterValidator::skipOnArray` so that filters like `trim` will not fail for array inputs

Fixes #2571: Fixed the bug that batchInsert will fail for SQLite if the values contain null or boolean false;
Fixes #2683: Fixed the bug that batchInsert will fail for MySQL if the values contain boolean false.

fix sql query

fixes #2739

Fixes #2740