Improved ACL2 :doc topic EQUALITY-VARIANTS-DETAILS after feedback from
David Rager.

Fixed issues from rendering to text from original ~bf[]..~ef[]
directives.

In Makefile, updated "Section: Building the XDOC combined manual", in
particular removing a tentative target for fast build of the
text-based combined manual, system/doc/rendered-doc-combined.lsp

Miscellaneous ACL2-Doc (Emacs documentation browser) improvements:

- Default initialization uses acl2+books combined manual if its data
  file exists.

- Movement commands all show current topic in message under mode line
  (not just search).

- Arranged for mode line to show acl2-doc (display) buffer as not
  modified.

- Updated :doc acl2-doc to clarify that all topic names (including
  links) are with respect to the ACL2 package.

- Added "h" command for help (by going to the ACL2-DOC topic).

- No longer eliminate topics with vertical bars and spaces --
  hopefully there aren't any, due to changes in community books
  system/doc/render*.lisp.


git-svn-id: http://acl2-devel.googlecode.com/svn/trunk@1153 5d84a466-a78b-0930-a311-59b22171a541