MAC Support

Added support for MACs in messages, this still isn't totally read
because the creation of shared-secrets still need to be made.

FormMain:
- Minor renaming of TabPages.
IpCommunication:
- Messages will now be resend until an ACK is received. This needs a
timeout though.
- Renamed "Close" to "Stop".
ChatTwo_Protocol:
- Made "MessageTransmissionHandler" fire an event.