Rename struct device to class Device
Move devicelist to MaxRFProto.cpp

This allows the message parsing methods to also use the device list,
which is needed to parse Ack messages (which have a different format
depending on the type of the sender).
Add a "DEVICE_UNKNOWN" device type
Add enum for the message types
When parsing a message, also find the corresponding device state
Also print the device name when printing a message
Move state updates into MaxRFMessage
Don't add the broadcast address as a device
Parse and process AckMessages
Convert lookup tables to functions

This allows placing the resulting strings in PROGMEM and makes it easier
to convert to C++11 enum classes later on.
Put some more strings in PROGMEM

The previous commit moved a few strings from inside an array definition
into a function, allowing to use the F() macro on them.
Convert enums to enum C++11 classes

These enum classes have more explicit scoping, are stricter with
implicit casting rules and allow specifying an explicit storage size.
Give enum classes a storage type

This makes the compile use only one byte to store each of these enum
values.
Comment out hardcoded device definitions

These are only useful for my particular setup, but I'll leave them in as
an example.