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)
Consistent getting table schema in CActiveRecord

$this->getMetaData()->tableSchema replaced with $this->getTableSchema() in CActiveRecord::insert(), CActiveRecord::getPrimaryKey() and CActiveRecord::setPrimaryKey() to match usage in other methods.
Issue #2653: updated Markdown Extra Lib to version 1.3
Add RESTful method support for html forms

This commit allows calls to `CHtml::form()`, `CHtml::beginForm`
`CActiveForm::$method` etc to accept verbs other than `post` and `get`,
e.g. `delete`, `put`, `patch` etc

This is implemented by detecting non `post`, `get`, converting to `post`
 and adding a hidden `_method` field, similar to how CSRF protection works.
update changelog
add absolutePaths option to CFileHelper::findFiles

if absolutePaths is true (by default), function will return absolute paths, otherwise the relative ones
mbstring fallback for CFileHelper::findFiles
Ability to substitute model attribute name, to use custom data getter. It is not dangerous to use any custom fields and getters, because it will work for read-only.
fix #2378 CActiveRecord::tableName() in namespaced model
removed occasional FormInput file
Double condition applying for Active Record relation lazy loading has been fixed.
Issue #2756 has been added to CHANGELOG
Merge pull request #2759 from Blizzke/master

[NL] Updated translation for latest release
code conv fix, charset specifying and docs improvement
Merge remote-tracking branch 'upstream/master' into patch-1
CHANGELOG updated
phpdoc fix for CActiveRecord
Merge pull request #2769 from gureedo/phpdoc-patch

phpdoc fix for CActiveRecord
Merge remote-tracking branch 'upstream/master'