optimized newsletter overview

no more deleting, duplicating only adding is allowed
removed editDialog and show only one button with text
added tabPanel settings var for better extending of Kwf_js/Binding/TabPanel

this settings will be applyed to the tabpanel
added own preview tab for newsletter system

shows html/text preview of newsletter
switch between newsletter subscriber for preview
send test preview newsletter to any email for any subsriber
using new tabpanel for newsletter system

now a prev/next button in the bbar will be shown to easily switch between tabs
adding trackingPixel to Kwc/Mail/Abstract

tracks views of mail if user shows all images
added this tracking evaluation to newsletter statistic