Revert "Forms: BaseControl::formatMessage() moved to Validator, exportRules() moved to Helpers"

This reverts commit 8f25b3cfc3ddd6eff0bdb5f2ce40885b65cb8e50.
Revert "Forms: all validators and $defaultMessages moved to new class Nette\Forms\Validator (BC break if you are calling these methods directly)"

This reverts commit f7eaa902937b59b234e76103efd9278fd29e0e8d.
Forms: added validators NOT_EQUAL & BLANK
Revert: Forms: used data('nette-***') instead of attrs['data-nette-***']
Revert "Forms: error message formatting moved from Rules to BaseControl"

This reverts commit 01bb61e4f70f3913018ad6d074d2989ae9027930.