Add user-selectable pretty-printing option for showing long-form names.

[brianhuffman]

Names in saw-script are based on globally-unique URIs that also have one or more shorter "preferred" names to be used for parsing and printing. Currently pretty printing is inconsistent: Some commands display the short-form names, while others display the long URI names (see #1277 and #1607).

We should consistently use the short-form names for all pretty-printing commands. But we should also add a user-selectable option (e.g. a command like set_long_names true) that tells the pretty-printer to use long-form names, for those situations where a user would like to see them for debugging purposes.

[sauclovian-g]

also see #747