Introduced new legacy-orphans subtopic of legacy-documentation, which
currently contains switches-parameters-and-modes (and hence the latter
topic is no longer at the top level).  This closes acl2-books issue
162.


git-svn-id: http://acl2-devel.googlecode.com/svn/trunk@1263 5d84a466-a78b-0930-a311-59b22171a541