Custom Data Plugin

[SocraticPhoenix]

Now that the Data API is reasonably stable, and the data abstractions from common have made it into the main api, a plugin should be written that shows usage of custom data. I know this kind of example would be very useful to me., and I'm sure many others would benefit as well. I think that, in general, the example should include:

• Single data (both primitive, and string-convertible)
• Multi-Data
• Everything required to make the data "work" and be serialized/peristent

(I would write it myself, but I would need some sort of example plugin to follow before I got the hang of it)

[Faithcaio]

@gabizou 0d93861
If you'd like to take a look

[phit]

was covered by #17