Have Message Details better reflect dynamic message information.

The current Message Details are ambiguous when displaying details. As well,  @c00w noticed that pending messages are being shown as sent in the message details when in fact they haven't been ( #519 ) which I have been able to reproduce.
This pull request does the following:

-Distinguishes between sent and received messages.
-Displays whether message is sent, pending, or failed.
-Replaces 'Sender:' label with 'To:' and 'From:' labels, depending on whether message is sent or received.
-Replaces 'Sent/Received: ' with respective 'Sent': and 'Received:' labels
-Replaces 'Transport:' label with 'Type:' label. 
-Lists recipients of group messages. (currently listed as 'Unknown').
-Removed timezone and seconds strings from date/time details.