last batch of edits

Hi all,
attached is my last batch of suggested edits to the usage guide. After
all the editorial changes, it drops the appendices because the SPDL/SPAT
appendix comes out of the blue without any explanations and it would
require quite a lot of addition, and because the links appendix only
contains three links which are already all linked previously.

Also, you may notice that I removed the mention of WSDL-S, which while
factually correct would not serve a useful purpose in this document, I
expect; in fact it could confuse the reader as to the status of WSDL-S
and SAWSDL.

These things will be discussed in the telcon.
Jacek