Remove API doc for dijit._underlay.   People should be accessing the underlay via !DialogUnderlay.show() and hide().  Refs #8017 !strict.

git-svn-id: http://svn.dojotoolkit.org/src/dijit/trunk@31409 560b804f-0ae3-0310-86f3-f6aa0a117693
(cherry picked from commit 2a50fd28028b39fceada1e8708f6fc1dfde07be1)
fix api doc for defer(), refs #14808
(cherry picked from commit e6c95fea9087099b73e735f00ac4fcc6cde0eff0)
Stop printing attr() deprecation warning.
Since 2.0 presumably won't have set()/get() methods, there's no
point upgrading existing code to use those methods.

Refs #10839.
(cherry picked from commit 59323f72ec1b98270fec565da6d30efd96fd7fbe)