Moving Cake\Error\Exception to Cake\Core\Error
Update Validator.php

Validator::add() - Typo in doc block
Update link to documentation
Fix link to documentation
Merge pull request #4427 from gmansilla/patch-2

Update link to documentation
Merge pull request #4428 from gmansilla/patch-4

Fixing links to 3.0 documentation
Merge remote-tracking branch 'origin/3.0' into 3.0-move-exception

Conflicts:
	src/Cache/CacheRegistry.php
	src/Core/Configure.php
Core\Error -> Core\Exception
Moving File and Folder to their own namespace
Validating mimetypes now require ext/fileinfo

Validating files must be done carefully, and File::mime() is too helpful
to be realiable. This also removes the dependency from Validation to
Filesystem
Removing the magic localized validation in the Validation class

This can be done much nicer and cleaner using validation providers
with the Validator class.
Removing whitespace
Merge remote-tracking branch 'origin/3.0' into 3.0-cleaner-validation

Conflicts:
	src/Validation/Validation.php
Merge branch '3.0-cleaner-validation' of github.com:cakephp/cakephp into 3.0-cleaner-validation
fix test
move fromReadableSize to parseFileSize
Add Validation::uploadedFile()

Add a simple wraper function for the various file validation methods.
This method makes it easier to wrap up the various file validators into
one method.

Refs #4456
Make uploadError() and uploadedFile() accept missing files.

This makes validating forms where there is an optional file much easier.
Make missing files pass validation when optional flag is used.
Validaiton requires on on seingle method in the Utility package

This still means that there should be a requirement in composer.json