[SAGA-RG] Suggested errata to the SD spec

[Steve Fisher]

Hi,

We would like to get rid of the URL passed into the discoverer
constructor. Its comment is:

"the url specified as in input parameter is to assist the
implementation to locate the underlying information system such that
it can be queried"

The problem we have is that this does not work with an adapter based
implementation as the URL is normally specific to the adapter. This
information can be passed to the adapter using a configuration file or
an environment variable according to the style adpopted by the adaper
writer.

The constructor then just has the session handle

The other change is to make the attribute names consistent with the
rest of SAGA - i.e. CamelCased

Steve