Changed elasticsearch AR primary key handling

now supports mapped primary key when _id is part of source with an
alias.
reverted primaryKey of elasticsearch to be array again

meet the AR interface requirements.
improved error reporting
Update yii.php
Removed exception translation, updated translations
Italian Translation Typo Fix
Changed Mongo → MongoDB in exception messages and logs
Update Language Translation
fixed de translation
Better names for PHP error-exceptions
fixed german translation
Added missing translation for Russian messages
Fixed italian translation
Fixes #1866: fixed German translation message
Updated copyright on title

I assume you’d want this to be updated to 2014.
Edited existing content, sketched out "Creating Your Own Behavior"

Undoubtedly will need to update “Creating Your Own Behavior” to reflect
changes in Yii 2.
Add Chinese translation

Signed-off-by: qiansen1386 <qiansen1386@gmail.com>
polish the Translation
Continue to polish chinese Translation. Fix all the issue mentioned by @samdark. Removed all comments.

Signed-off-by: qiansen1386 <qiansen1386@gmail.com>
Polish Chinese translation. Symbols

Signed-off-by: qiansen1386 <qiansen1386@gmail.com>