Added getter for cell contents to CGridColumn

Added getters to CGridColumn to allow getting cell contents
for extended use cases of CGridView.

issue #106
Enhance CJSON with JsonSerializable support (#2540)
Fixed disrespect of overrides of CActiveRecord::attributeNames()
Test case "CActiveRecordTest::testCustomAttributes()" has been added.
Code style at "CActiveRecord" has been fixed.
"CActiveRecord::_attributes" has been renamed to "CActiveRecord::_dbAttributes".
Merge branch 'pr-2569-ar-attributes'
Redundant has been removed from "CActiveRecord::refresh()"
Redundant condition for "names" has been removed from "CActiveRecord::getAttributes()"
PR #2569 has been reverted.
Fixes #1794: added ability to change widget ID via $htmlOptions['id'] array item in:

CTabView, CBaseListView, CListView, CGridView, CDetailView, CMenu, and CPortlet
Changelog line related to #1794.
Fixed unnecessary closing PHP tag in docblock.
Additional note related to #2107.
Fixes #100. Fixes #2180. CLogFilter::$logVars can now be array of arrays.
Fixes #1909: CGridView::$filterSelector prevents default action.
Fixes #196.
Less overhead.
Merge pull request #2593 from resurtm/fixes-196

Fixes #196: error summary models list is now customizable when using AJAX validation
Array checking.