DOM L2 Tests Committed

The DOM L2 tests have been committed.  I did not add the 
three files previously mentioned, so the older version of these 
should still be there.

There is a new file, staffNS.xml, and probably some supporting 
files -- do we want these in files/level2, and should be provide 
copies of the staff.xml that is in files/level1 here as well?

There are a number of problems with the tests:

- assert id's need to be changed to something useful
- suspect problems with processing firstChild elements -- upon 
  further investigation -- this actually worked with a previous 
  version of the support files -- not sure which, though -- but I 
  would suspect previous mod's to account for firstChild
- The import tests have some errors -- there are too many assert's 
   which I believe should be part of a large if statement -- will 
   investigate further.

--Mary