[cddlm] test docs

[Steve Loughran]

Stuart,

I've moved the api test doc under doc/test , and split out one for 
system testing into the same directory. Both are .doc format. And the 
api doc has been updated with changes discussed on the phone, plus some 
ones I did yesterday.

I'm cheating and using header numbering to number my tests. This is 
cheating as when stuff moves around, they change. We really need a 
proper naming scheme.

-steve