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)
IDNA2 fix
Changelog
Added CEmailValidator fix
Merge pull request #2602 from creocoder/idna2-fix

IDNA2 fix
Additions to #2602:

1. Proper Net_IDNA2 usage. Net_IDNA2::decode() and Net_IDNA2::encode()
accepts only domains, not full URLs. Before this fix framework used
to pass full URLs which is wrong usage.

2. If CEmailValidator or CUrlValidator is being used under PHP 5.3.0+,
native `idn` PHP extension will be used (`idn_to_utf8` and `idn_to_ascii`
functions in particular). Otherwise Net_IDNA2 will be used (for PHP
< 5.3.0).
Fixes #2053:

1. CPasswordHelper has been refactored.

2. CSecurityManager has been enhanced and now able to generate
cryptographically strong random stuff.
UPGRADE note related to #2053.
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.
added note about one should always review gii-generated model validation rules
ru: updated zii messages
ru: updated definitive guide
ru: translated comments in blog tutorial
ru: typo fixes
CSecurityManager:

1. Added /dev/urandom usage.
2. A couple of minor code optimizations.
Non-blocking read from /dev/random is not supported by RedHat 6.*.
Minor CS fixes and @throws docblock clause added.
(CModel::prependValidator(), CModel::appendValidator()) (Enh #2259 rework)
Docblocks fixes and other minor adjustements made.