Added support for moving the ACL2 system documentation into the XDOC
system.
**NOTE**: Please do not yet edit these files unless you're me or
          Jared!  I plan to send an announcement about all this soon.

The above support is provided by the new system/doc/ directory, which
contains files written by Jared Davis that were updated by both him
and me.  See system/doc/README.

Note that svn revision 2166 of books/xdoc/preprocess.lisp from the
jared/ branch has not yet been committed to the trunk, as Jared asked
me to wait to do that.  (However, I used the updated preprocess.lisp
to create new ACL2 source file doc.lisp.)

A separate check-in to acl2-devel will provide additional support for
moving the ACL2 system documentation into the XDOC fold.

Very minor note: In creating system/doc/acl2-doc.lisp, certification
of export-acl2doc.lisp created "hard symbol to link nicely" messages
in export-acl2doc.cert.out for the following preprocessor directives.
We might or might not want to fix these manually at some point.  I
looked at the acl2-pc::macro-command topic and found three such links,
all of which worked, so this seems like a very low priority cosmetic
issue.

  @(url ACL2-PC::UNDO)
  @(url ACL2-PC::COMM)
  @(url ACL2-PC::COMMANDS)
  @(url ACL2-PC::FORWARDCHAIN)
  @(url ACL2-PC::RETRIEVE)
  @(url ACL2-PC::UNSAVE)
  @(url ACL2-PC::SAVE)


git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2168 303c5b2c-9740-0410-b014-fd8f9db7be32
gl: add optimized symbolic subtraction, logeqv

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2173 303c5b2c-9740-0410-b014-fd8f9db7be32
Actually do the merge correctly...?

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2177 303c5b2c-9740-0410-b014-fd8f9db7be32
Various updates:

std/util:
 - Add /// support to deflist and defprojection
 - Use with-output to reduce output from deflist and defprojection
 - Tweak defenum to avoid dependency on deflist

xdoc:
 - Add basic books release-notes topic (not yet integrated into centaur/doc)
 - Tweak fancy viewer to warn Safari users about lack of proper history.state
   api support.

Minor tweaks to .gitignore files

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2178 303c5b2c-9740-0410-b014-fd8f9db7be32

Avoid accidental, futile attempt to certify rendered-doc.lisp, by
calling it rendered-doc.lsp instead.

Updated documentation for NOTE-6-4 and DOCUMENTATION.  The latter may
be improved in the future.

Modified system/doc/render-doc.lisp so that its output file,
system/doc/rendered-doc.lsp, would be printed in the ACL2 package.
(Avoiding package prefixes can be helpful for writing Emacs tools to
browse that output file.)


git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2179 303c5b2c-9740-0410-b014-fd8f9db7be32
Misc. fixes, including fixes to the documentation for DOC and DOCUMENTATION.

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2180 303c5b2c-9740-0410-b014-fd8f9db7be32