Updated Readme.html to state that it is deprecated and explain the "path forward."

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2572 303c5b2c-9740-0410-b014-fd8f9db7be32
More VL updates toward SystemVerilog:
  - Implement parsing/representation/printing support for tagged
    union expressions
  - Clean up use-set code
  - Move append-domains out of vl, rename to append-alist-vals, add append-alist-keys (fixes issue 93)

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2573 303c5b2c-9740-0410-b014-fd8f9db7be32