Since classical messages are not deleted when show_emails setting is
set to "0" and remain in the database, they should be shown
somewhere. Otherwise they may reappear later when the setting is
enabled again.
New `dc_msg_is_bot()` C API and corresponding `Message.is_bot()`
Python API can be used to check if incoming message is sent by a bot,
e.g. to avoid two echo bots replying indefinitely to each other.
"Bot" flag is not set for outgoing messages, but may be set for
BCC-self messages. For now documentation says that `dc_msg_is_bot()`
return value is unspecified for outgoing messages. It can be better
specified later if needed for specific applications, e.g. sharing an
account with a helper bot.
the default account created by dc_accounts_new()
is annoying when doing a migrate/import account;
in this case, you must not forget to remove the default account.
in between you have two account,
and accounts are swiched.
it seems to be better
to just call add_account() on a new account object as needed.
systemli.org seems not to include Received: header in messages sent to
self, including BCC-self and messages sent to Saved message chat. This
results in all these messages not being displayed on other devices in
multi-device setting. To work around this problem we restrict draft
detection based on Received: header to classical mails.
Delta Chat already implements proper draft detection based on the
\Draft message flag and \Drafts folder flag. However, Thunderbird does
not set \Draft flag when message is stored as "Template". To make
draft detection for Thunderbird more robust, in case Received: header
check is removed altogether later, we check for X-Mozilla-Draft-Info
header which Thunderbird sets both for "Drafts" and "Templates".
probably they come in by the latest sqlx<->rusqlite moves,
however, as they are followed by subsequent migrations,
that should not have been a big bug in the past
(maybe unless the app was killed at a bad moment)
Even if chat has no messages, contacts should not be deleted.
Otherwise chat will reference invalid contact ID which can't be loaded
from the database, resulting in broken contact list in group chats.
`Imap` structure is always created in a configured state now. There is
no default value for `ImapConfig` anymore.
Also resultify Scheduler::start() to fail on database errors, for
example if IMAP configuration cannot be read from the database during
`start_io()`. Previosuly errors during reading keys such as
`mvbox_watch` were simply ignored and folders were not watched until
the application is completely restarted, now start_io() will fail and
scheduler will only be started at the next start_io() call which
usually happens when app is brought to the foreground.
