CsrfProtection: token is expired after regenerateId() (i.e. after logout) [Closes #36]
CSRF: better error message

Conflicts:
	src/Forms/Validator.php
adding a support for rendering an id HTML attribute into default renderer

added tests for group id option
netteforms.js: Change order of showing error message and focusing element. In Firefox element lost focus when alert is invoked.
RadioList: added item label prototype [fixes #31]
Container: added addMultiUpload()
TextBase: added setMaxLength()