Improve connection process

Keep bad connection attempts from freezing interface.

Milestone changed to 1.4

Fixed a bug in communication code that could lead to freezes on connection in 89ced57a. Still has a chance to freeze interface in some cases, though.

Most connection problems resolved by adding crystal to xmega in dstat-hardware@ef2927db and adding the restart command in dstat-firmware@d5a82134 (supported in interface e9330d16, but not merged yet as it doesn't work properly if the serial device name changes after reset---will be fixed by #23 (closed))

closed