Make digests more reliable

Instead of checking 1000 messages max once a day, we now grab all
digests once a day and then send one digest after sending due messages.
And if the digest has a lot of mails (at least 3 people are subscribed
to build_success PER_WEEK, which are a LOT of emails), we send several
mails - 300 per digest.

This makes sure we don't forget digests, the current downside is that
we send digests of all kind if hermesworker restarts. If people complain
(if we happen to restart several times a day PER_WEEK becomes useless)
we need to either have a timestamp in file system or database. But that
is not as simple either as just because we grabed digests doesn't mean
the digests are sent out. One possible measure is to save per (digest)
subscribtion when the last mail was sent out and use that to limit how
often we regrab it.
reduce the log output of hermesgenerator a bit
- added expansion of request diff parameter
- minor cleanups
- fix revision parameter for requests
- enable cronolog parameter for logging.
remove even more log for 'info'
fix date of immediate sent mail messages
new overview diagram
Merge branch '0.8' of gitorious.org:opensuse/hermes into 0.8
added missing perl modules to INSTALL file
silence warning on undefined value
Merge commit 'dhl/0.8^' into 0.8
Gitignore starship logfiles
Improve logging
Fixed regexp filter
Fixing replyto in sendMail
Change debugmail savedir to /tmp (which actually is ugly)
Unclear changes in notifications (maybe line ending?)
Show more details about undelivered messages
Fixed missing semicolon
Adding new unsentMessagesDetail to Export