Inconsistent parameter types and little problems in ezcMailImapTransport

In ezcMailImapTransport (I don't know if the same applies to other classes) the message id parameters are sometimes arrays, sometimes strings and sometimes int. Sometimes they are called $messages, sometimes $msgNum, sometimes $number.

For example in copyMessages it is a string. This is flexible, as you can pass "1,3,4" or "1:3" or even "2,4:7,9,12:*".
fetchSizes() expects an array, which is join()ed inside the method. This restricts to only comma-separated usage, something like "3:*" is not possible (besides using listmessages() to get all ids and then pass this big array). The same happens in fetchFlags() and sort().

In delete() it is called $msgNum and has to be an int, but it is used the same way as in copyMessages(), to be flexible it should be a string. Then you don't have to call delete() 1000 times if you want to delete 1000 messages.

Minor problems exist in fetchSizes() and fetchFlags. $messages has to be an array, so this is not working:
throw new ezcMailTransportException( "The IMAP server could not fetch flags for the messages '{$messages}': {$response}." );
If $messages is a string (see above) this problem will disappear.