ACTION-153 and ACTION-112: Updates to privacy requirements

I've tried to streamline the privacy requirements document per  
ACTION-153 (I think this also closes out ACTION-112 that I took at the  
F2F). The text attached below reflects a number of changes:

-- I removed the use cases, since they were about user and application  
policies, not about API requirements. I think we will be able to use  
them later when we get to defining how the user expectations/ 
preferences/policies will work. I also removed the discussions under  
the individual privacy elements that were about policies rather than  
API requirements.

-- I re-ordered the remainder of the text so that it's more clear  
which pieces of the privacy work are going where.

-- I changed the table that shows the breakdown of how we're dealing  
with the various elements of privacy, and I added in the ones that  
were missing from the table.

I tried not to alter much of the text otherwise. John and I definitely  
have some more substantive issues with some of the language in this  
doc, but for the purposes of streamlining I mostly left the text as it  
was. He and I will send comments to the list about our outstanding  
issues (before or after FPWD, as appropriate).

I know this is a little late for the Wednesday call, but if it's  
possible for one of the editors to post the text below, it will be a  
lot easier to read (I don't have editorial access).

Cheers
Alissa