===== Synopsis =====

$mailbox_1 = Mail::imapsync::mailbox->new();
$mailbox_2 = Mail::imapsync::mailbox->new();


$mailbox_1->host('imap1.lala.org');
$mailbox_1->user('toto1');
...

$mailbox_2->host('imap2.lala.org');
$mailbox_2->user('toto2');
...


$transfer = Mail::imapsync::transfer->new();
$transfer->sync($mailbox_1, $mailbox_2);


- an object for  mailbox 
- an object for a transfer
- ?an object for a folder?
- ?an object for a message?