[ogsa-d-wg] Updated Architecture Document

Attached is an updated architecture document for your review and comment, It includes the following changes: 1. Updated data access section from Mario. 2. Updated federation section based upon last week's teleconference 3. Updated and reorganized security information. This is my attempt to incorporate changes from GGF-15. As a reminder: I currently hold the document write lock. Mario has a sub-lock on the Data Access section Allen