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 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
code conv fix, charset specifying and docs improvement
Merge remote-tracking branch 'upstream/master' into patch-1
CHANGELOG updated
Merge remote-tracking branch 'upstream/master'
another way to return relative paths: findFilesRecursive main loop instead of findFiles post-processing
CClientScriptTest has been advanced to expose issue #2770
CClientScript::renderScriptBatch() has been fixed to group scripts with different HTML options correctly.
Issue #2770 has been added to CHANGELOG
CClientScript::renderScriptBatch() has been improved to sort html options only if they are specified.
Merge branch 'master' of github.com:yiisoft/yii into 2770-client-script-render-script-batch
cache dir creation with correct file mod