Fixed a bug that date-/time inputs are rendered with a size=0 and/or maxlength=0.

Fixed a bug that Input fields are not rendered correctly the columntype are 'set' or 'enum'.
Support.php: doAttribute() - attributes with type 'size' or 'maxlenght' and no value or value=0 are skipped and not created.
AbstractBuild.php: a maxLenght formelement parameter needs to be numeric and (new) >0 to have an impact. Added calculation of maxlength for columntypes 'set' and 'enum': maxLengthSetEnum().