Instead of being a function it now expects a struct with the
PartialUserData trait implemented. This in part ensures the correct
function signature.
It also adds another optional function to PartialUserData that returns
definitions for the added methods.
Depending on the implemented traits the lua class will inherit from the
associated interface class.
It also specifies the constructor function for each of the devices.
This enforced the idea that all generics must be specified for the type
when using the device macro. It will also come into play later when the
Typed macro gets introduced, as the name will be used when generating
definitions.
Previously this could only be done by implementing a trait, like
`AddAdditionalMethods`, that that has an add_methods function where you
can put your custom methods. With this new attribute you can pass in a
register function directly!
This time with a bit more though put into the design of the code, as a
result the macro should be a lot more robust.
This did result in the macro getting renamed from LuaDevice to Device as
this should be _the_ Device macro.
The attribute also got renamed from traits() to device(traits()) and the
syntax got overhauled to allow for a bit more expression.
