Peek reipients, fetch existing messages

Read all of an e-mail accounts messages and extract all To/CC addresses
if the From was from our own account.
Then, fetch existing messages from the server and show them.

Also, I fixed two other things:
- just by chance my test failed because of an completely unrelated bug.
The bug: bcc_self messages were not marked as read if mvbox_move was set
to true.
- add some color to the test output (minor change)

src/imap/idle.rs

@@ -160,7 +160,7 @@ impl Imap {
                     // will not find any new.
 
                     if let Some(ref watch_folder) = watch_folder {
-                        match self.fetch_new_messages(context, watch_folder).await {
+                        match self.fetch_new_messages(context, watch_folder, false).await {
                             Ok(res) => {
                                 info!(context, "fetch_new_messages returned {:?}", res);
                                 if res {