Tweaked Quicklisp setup to avoid problem with relative :path

Documentation updates and other minor reorganization

 - Moved memoize/ into centaur/ since it's extremely preliminary and doesn't
   "deserve" to be at the top level.

 - Moved centaur/doc.lisp and release notes into a new doc/ directory, and
   updated various books, Makefiles, documentation, etc., accordingly.

 - Extended FIX-THE-HIERARCHY with new homes for all topics from the "Switches,
   Parameters, and Modes" section.  Perhaps we can merge these changes into
   acl2-doc.lisp soon.

 - Reduced slightly the amount of information in centaur/README.html, toward
   DRYer documentation.

Update issue 4

I added some new, very preliminary documentation about best practices for the
books, see doc/practices.lisp.  Perhaps this can be a starting point for
further discussion.

I tweaked the cowles package to better match what it says in the best-practices
documentation.

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2501 303c5b2c-9740-0410-b014-fd8f9db7be32
Adding an inst directory

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2502 303c5b2c-9740-0410-b014-fd8f9db7be32
Make quicklisp_clean more particular and added a variable that configures curl for using a proxy.  Note that this does nothing for making quicklisp itself use a proxy, which still has to be done manually for the first time you use a quicklisp install.

Update issue 144

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2503 303c5b2c-9740-0410-b014-fd8f9db7be32
Quoting comments in (defxdoc note-6-5 ...):

; Improved error message for bad calls of with-local-stobj, especially when the
; indicated creator function (whether or not provided explicitly) is wrong.
; Thanks to Jared Davis for bringing this issue to our attention.

; Added new :doc topic, type-alist, and added links to it.  Thanks to David
; Rager fof discussions leading to this addition.

Quoting :doc note-6-5:

  The keyword commands :exit and :quit are disabled inside [brr], in
  order to avoid accidental exits from ACL2. Thanks to David Rager
  for suggesting such a change.

Added mention of brr@ at the end of :doc brr-commands, and then
eliminated brr-commands as an extra parent of brr@.  Thanks to David
Rager for a discussion leading to these changes.

In GNUmakefile, added a hack: if ACL2_SAVE_QUICKLISP is defined, then
quicklisp files won't be cleaned.  As the comment there says, this
hack can easily be removed -- in fact, probably after today, since
Jared tells me he is making a change to address the current quicklisp
issue (in fact I think he made it during my testing).

NOTE: I ran an "everything" regression successfully twice, where 2501
was committed during the first run, then I updated to 2502, and then
2503 committed during the second run.  So I'm updating to 2503 without
further testing, since that change is orthogonal to what I've done.


git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2504 303c5b2c-9740-0410-b014-fd8f9db7be32