Significantly speed up the fancy xdoc viewer. (fixes issue 134)

Previously, the jump-to box was rendering every :short string (XML -> TEXT) at
xdoc startup time.  This (embarassingly simple) patch avoids this, and does the
rendering lazily, only as needed, so the page loads way faster.  As an added
bonus, we no longer need the hogan library.

This is a viewer-only change that should be compatible with previously
generated manuals, e.g., for ACL2 6.4.

I suspect it isn't worth the time to tinker with the format of xindex.js for
now (which is sort of a shame, because I spent a fair bit of time thinking up
how to do that).  We can eventually tweak it if we need to, but I think this
patch will make performance acceptable for most users.  (Of course, please
report any experiences to the contrary...)

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2440 303c5b2c-9740-0410-b014-fd8f9db7be32
defdata events in base.lisp are now in verbose mode, so that we can count the number of defuns and defthms in the .cert.out file

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2441 303c5b2c-9740-0410-b014-fd8f9db7be32
tweak xdoc text display to show URLs for external links (fixes issue 137)

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2442 303c5b2c-9740-0410-b014-fd8f9db7be32
fix but with recent fancy viewer update

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2443 303c5b2c-9740-0410-b014-fd8f9db7be32
removed an unneeded defthm and removed history from output-list in defdata

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2444 303c5b2c-9740-0410-b014-fd8f9db7be32