ACTION-307 Propose language based on McCormick's slides

Here's my crack at it. Since we're driving towards FPWD of the rec track 
document, this will be on today's agenda as well. 



Add this to to the bottom of section 5.2, additional security context:


The user agent MUST reduce the state of all security context information 
made available to a single value. The set of values MUST be strictly 
comparable. 

The user agent MUST make the security context information value available 
to the end user, in either primary or secondary chrome. 

The user agent MUST make formula by which the value is calculated 
available to the end user. Documentation of the user agent is the 
likeliest place. 

The form of the indicator of this value will depend on the user agent and 
end user abilities. The user agent SHOULD provide a the indicator primary 
chrome.