fixed link macro (url_escape was called twice)
added new "link" feature to message macro
unified "hint" and common message macro
added EnvironmentWarning to header
WebInterfaceDataset replaces CryptoBoxWebserverSettings
WebInterfaceSites replaces CryptoBoxWebserverSites
input validation rewritten
clearsiler macro 'print_form_header' now expects the 'action' as a parameter