Draft update to landmarks section for APG 1.1

Matt,

Ann, Teresa and I have been meeting twice a week to work on updating the Landmarks section.

Here is the latest proposed changes, we still have some work to do:
https://rawgit.com/jongund/aria/master/practices/aria-practices.html#aria_landmark 

There is a new Section 2 titled: Design Patterns Landmark Roles

Jon