Serialization for D. Comments, please!

[BCS]

Reply to grauzone,

>>> Is there any real reason for all those mixins?
>>> 
>> which ones?
>> 
> All used by the user. That would be Serializable and
> SerializableRecuring.
> 

What else would you use? I guess if I really wanted to I could use the same 
device as for 3rd party types, but that just pushes the mixin to global scope 
(the functions have to be defined in the same module as the type or they 
won't be able to access private members) and introduces unneeded performance 
issues from using function pointers.

If you can spot a better solution, I'm all for it, but I don't see one and 
don't think this solution is to bad.