Fixups for release 0.6
Initial tests for wumpus rover.  Add tests for roles to seperate helicopters and rovers.
Add role for helicopters
Add role for rovers
Add driver for WumpusRover
Stub connect method
Test and stub module for ArduPilot packet parsing
Parse packets correctly.  Throw exceptions for bad header and checksum
Ack packet implemented.  Fix how the Packet role is loaded.
Implement a default convience BUILDARGS for packets.  Logger role can have its _logger() method called as a class method.  PacketFactory passes 'fresh' param for packets that are built as we go.
Write out Ack packets
Correctly handle checksums
Define messages that we need to implement
Implement RequestStartupMessage packets
Implement StartupMessage packet
Implement RadioTrims packet
RadioMins packet implemented
Implement RadioMaxes packets.  Add test for writing packets (which fails as of this commit).
Get rid of need for _encode_payload_for_write in packet implementations.  All tests pass.
Minor whitespace change