[RIF][DC] Reworked Design Constraints page

Hi all,

to complete the action I had from the last telecon [1], I reworked the 
wiki on Design Constraints [2]. Please have a look at it, contribute, 
and let us start the discussion.

I propose to use [DC] as the topic for emails about Design Constraints. 
I strongly suggest that everybody in the WG should subscribe to changes 
on the DC page [2].

Christian

[1] ACTION: csma to modify design constraint template to take into 
acccount what was said today [recorded in 
http://www.w3.org/2006/03/28-rif-minutes.html#action12]

[2] http://www.w3.org/2005/rules/wg/wiki/Design_Constraints