Parse pseudo mail headers to set database fields

[rohieb]

We could let Ditzy parse the first lines of each signed message body, until the first double new line, to change certain data fields for the thread, just like the Debian Bug tracker does it. For example, the thread starter is currently taken from the first mail which has the "[antrag]" string in its subject, but this string is also mostly added by a vorstand member and not by the "real" applicant, so the respective vorstand member is set as the starter. Furthermore, we could implement a "done" field this way for each thread to de-clutter Ditzy's list.

Syntaxes I currently have in mind:

• starter John Doe (the Debian way)
• Ditzy: set starter "John Doe" (improved fault-tolerance against stray words)

Parsing of +1's can continue the way it's currently implemented.