make a PEEK verb which respects PEEK paths

[smurp]

Motivation

To facilitate display of literal information in the dataset which does not lend itself to portrayal as nodes, add a new verb PEEK which can be used to examine nodes. Since the amount of literal information can be both overwhelming and non-obviously linked to the node's in question there are needs for

• a way to specify the predicates whose values are to be displayed
• a way to indicate a possible path through adjoining subjects for traversal path to the desired info
• a way to indicate a precedence order for such traversal paths in case preferred data is unavailable

Approach

Consider SPARQL and OKBC chains of reference.

Consider UNIX $PATH syntax for precedence.