phpdocs of actions and improved error msg

Improve 'missing template' message and phpdocs of actions.
Hidden fields in fieldset cancel actions. Fixes #86

When fields were skipped, the $_ret was still false, which cancel the
action without warning.
Improved PHPDocs and visibility of fields
Merge pull request #88 from Klap-in/master

Let closed fieldset submit again & many PHPDocs improvements