DataSource - Need to describe the interface

[Hendy]

nuPickers had property editors for various combinations of a data-source + editor ui (hence Enum Typeahead List Picker didn't exist as it's an unlikely data-set to be used with a typeahead)

this new project will use a common data source for all property editors - essentially using something like the nuPicker DotNet for all data sources.

Enum
Json
Lucene
Relation
Sql
Xml

each data source need to be able to return the following for each option:
a string key (default to using the key instead of id ?)
a string label
a parent id (for a tree picker / cascading drop downs) ?

[ThomasSkyldahl]

just a small note: With the new Composition based approach in Umbraco, the IDataSource registration could also be Composition based