[zen-12] Working CSRF element
[zen-12] Working CSRF element

- Use session hash to validate
- Do not initialize CSRF token and session until element value attribute is
  retrieved (either via getAttribute('value') or getAttributes()) -- typically,
  this will only happen when rendering.

MadCat34/zend-form,marek-saji/zend-form,svycka/zend-form,MadCat34/zend-form,akrabat/zend-form,adamlundrigan/zend-form,marek-saji/zend-form,zendframework/zend-form,svycka/zend-form,akrabat/zend-form,adamlundrigan/zend-form,zendframework/zend-form