clean up remaining massmessage preview code
add find() and all() in model.Message
add message view
add message entity_url
create message events
hide message events from event streams
message tab in dashboard
move send from model to lib
add reply_to in lib.mail
use reply_to instaed of email_from
emit message event and notifications
enforce email_sent and force_resend
actually commit stuff to the database
allow to format email subject and body

this removes possibility to format the message itself,
e.g. using {name} as placeholder
add simple message wrapper
use message.send in massmessage
use message.send in message controller
update help texts