Fixes #1957. Add Primary Key syntax for MySql schema. Also adds support of an Array
of columns rather than just a string
Add changelog lines
Update CActiveForm.php

If 'errorMessageCssClass' is not specified explicitly, it will fall back to the default, specified with CHtml::$errorMessageCss
Update CActiveForm.php

Added version number to comment, minor styling fixes
Update CHANGELOG
Merge pull request #2231 from opus-online/activeform-fix-2223

Fix for #2223 - `CActiveForm::error` does not respect `CHtml::$errorMessageCss`
Minor CS fix (related to #2231).
Merge branch 'master' of github.com:yiisoft/yii into pr/2090

Conflicts:
	CHANGELOG
Enhancements to the #2090.
CS fix (related to #2090).
New core team members and emails of old members.