Partial fix for issue 1831 - dsconfig interactive mode.

With this change, dsconfig now prompts for component names if they are not specified on the command-line. Where more than one choice is available, dsconfig displays a list of choices. For create-xxx sub-commands dsconfig also prompts for  the component type (-t flag) if it is not specified. Users can, at this point, request help which displays a detailed description of each type.

A subsequent change will add support for interactively setting property values.

A major part of this change includes improvements to the type-safety of the client admin APIs (e.g. use of raw types), which were being flagged in the latest version of Eclipse (apologies: I should have committed these separately, but they got too tangled up in this change).