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)

python/src/deltachat/direct_imap.py

@@ -24,12 +24,13 @@ def dc_account_extra_configure(account):
     """ Reset the account (we reuse accounts across tests)
     and make 'account.direct_imap' available for direct IMAP ops.
     """
-    imap = DirectImap(account)
-    if imap.select_config_folder("mvbox"):
+    if not hasattr(account, "direct_imap"):
+        imap = DirectImap(account)
+        if imap.select_config_folder("mvbox"):
+            imap.delete(ALL, expunge=True)
+        assert imap.select_config_folder("inbox")
         imap.delete(ALL, expunge=True)
-    assert imap.select_config_folder("inbox")
-    imap.delete(ALL, expunge=True)
-    setattr(account, "direct_imap", imap)
+        setattr(account, "direct_imap", imap)
 
 
 @deltachat.global_hookimpl