Feature: new Signal Slot metadataAfterViewhelperdata called after the metaData has been populated from the Viewhelpers and before it is written into the page config
Feature: signal newMetadata has $params as second parameter
Bugfix: og:image got baseurl even if a qualified url was already present
New Viewhelper url.addprotocol which checks if an uri has a protocol and adds it if needed, default is http, can be set with the protocol attribute