sup for 2.0

[Gaute Hope <eg@gaute.vetsj.com>]

Greetings suppers,

I was thinking about setting up a branch for next generation sup, I have
partly switched to Mail (in stead of RMail) and started migrating to
using safe-ids in the index as opposed to the slightly modified
message-id and message-refs. I have put this in a sup-for-two branch
[1]. It is based on the discussion in issue 22 [2].

Anyway, my proposal is: we set up a sup-for-two branch on origin. The
things that should go in there are:
- maildir-sync
- Mail
- Id -> safe id change
- other big changes we want for sup-0.14 or the future

The only mature feature here is the maildir-sync branch (which I have
also based my Mail work on). I still think that we should merge in the
Mail work pretty soon because the change of id to safeid (also for all
refs) will be extra work to port later - given that we move to Mail.
There are some issues and unfinished things still:
- performance (about half of RMail)
- only implemented for maildir, not for mbox or for sending
- haven't figured out all threading logic [3]
- migration script for index [4] is incomplete (and it might not even be
really possible)

Mail is UTF-8 (but crashes on too nasty input [5]), I've started to
collect nasty emails for testing purposes.. we should add those to the
test-suite somehow. So far most UTF-8 issues seems to have been solved
by [6] and native UTF-8 in Mail. Tested on some 25k of email of
extremely varying quality.

Comments are appreciated.

Regards, Gaute


[1] https://github.com/gauteh/sup/tree/sup-for-two
[2] https://github.com/sup-heliotrope/sup/issues/22
[3] https://github.com/gauteh/sup/blob/sup-for-two/lib/sup/thread.rb#L299
[4] https://github.com/gauteh/sup/blob/sup-for-two/bin/sup-migrate-index
[5] https://github.com/mikel/mail/issues/544
[6] https://github.com/gauteh/sup/blob/sup-for-two/lib/sup/util.rb#L344