Moved most of the user-related logic into form models
Extracted password-related code into User model methods
Allow multilevel dropdown.
Added typecast database types into php types
Fixed bad example in mass assignment guide
Fixed mass assignment note
And another fix to mass assignment example
Revised model guide
Fixed constructor overriding to allow array configuration
refactored file validator.
fix kazakh translate
Fixes #2260.
Merge pull request #2259 from Asetss/master

fix kazakh translation
doc improvement.
doc fix.
Used setter as field
Added ! usage for default scenario example to model guide
Typo fix
Moved forms used in frontend only to frontend
override create