Add _endt to WidgetBase.php to solve a bug in datetime form widget.
New method WidgetBase::endOfTag() for jForm widgets

Refs #169
Vagrant configuration to test jelix <= 1.6.x
jForms - error decorator should erase list at verification start

After a second try of submit, error messages are still there. It is
annoying if the form is submitted with ajax.
vagrant - updatesrc.sh: reset temp directory at each sources update
Testapp - sample form: fixed a notice when displaying a textarea with input_html widget

input_html does not expect to receive a textarea control. So we
created a specific widget to display a "textarea" control as an input html.
Upgrade markitup to 1.1.14. Fix issue with our jquery version.
Markitup: add the markdown plugin