The DataSet Capability

I would like to introduce a DataSet capability to replace the Realm capability.

The idea of a DataSet is to be able to define a collection of WellKnown files, possibly of different types. Included in this capability would be the DataSetItem property, which would reference a set of WellKnown files.

There are several differences between Realms, as currently used, and DataSets.

1. Realms were subordinate to an application, while a DataSet may reference files from more than one application.
2. DataSets may not include Metadata.

The DataSet capability, like the WellKnown capability, is intended to support the sharing of data between users.

I'll also note that files with the DataSet capability can also have the WellKnown capability, facilitating the easy creation of a heirarchy of data collections. Also, a WellKnown file can belong to more than one DataSet.