Merge pull request #72 from lupo49/master

Added flag "skipempty" in thread-syntax to skip empty discussions in output
Do not print Hide/Show discussion toggle button / Added #picker3
Improve English title of discussion page add form
language string 'threads' is unused
Update Dutch translation
Merge pull request #74 from Klap-in/translationdutch

Translation update Dutch
Fix XSS vulnerability in handling of pre-filled text
Security release: Fix XSS vulnerability, thanks to Kazutaka Miyasaka

It was possible to pass arbitrary HTML code into the comment form via
the URL on any page where a discussion form was displayed. Thus you
should update to this release as soon as possible.
Replaced old DokuWiki JavaScript library use by jQuery

This makes the plugin compatible with the next DokuWiki release. The
whole JavaScript code of the plugin should be refactored later.
French translation update by @pierreyvesbaloche - thanks! closes #78
Add explicit type information to event-parameters
Fix the @DATE@ placeholder in the thread template