Improvements all around. Implemented and interruptible RollingQueue, used for
holding messages. Added priority levels for transports. Made Ctrl+C
instantaneously stop all roles as long as they are waiting on the correct event
objects. Made reception thread respect timeout more strictly.
More explicit message about which serializer is used
New implementation of importFile, which does not clutter up the module namespace.
Support being interrupted during the initial wait.
Add some more log messages for system startup/shutdown.
Implement bluetooth transport, and add bluetoothnet network to test it.