deferred validation

Added support of deferred to ```ActiveForm``` validation.
deferred validation

Added support of deferred validation.
Update yii.activeForm.js

remove empty message arrays
Update yii.activeForm.js
Update input-validation.md
fixed typo and some links
Merge pull request #4510 from xBazilio/patch-3

fixed typo and some links
Grammar fix
add start-installation.md
up errors translate
up image url
Merge pull request #4513 from RichWeber/master

[Uk][Guide] Add page translation
make Request more robust against invalid CSRF data

fixes #4514
add start-workflow.md
class map
fix errors
minor message improvements
Revert "Used substr_compare instead of substr when we don't care about result"

This reverts commit 07f01bcf2bb7725eab00cd5a22cc0c79161702b2.

BUT ONLY for the /build directory!
phpdoc
code style