Slideshow bugfixes and sync with ox-html function name changes.

* contrib/lisp/ox-deck.el: Default org-deck-directories to "./deck.js".
(org-deck-toc): Sync w/ ox-html name change (org-html--toc-text.)
(org-deck-inner-template): Remove duplicate toc generation code.
* contrib/lisp/ox-s5.el: Add inner template to fix duplicate content
  div error.
(org-s5-toc): Sync w/ ox-html name change (org-html--toc-text) and
make toc entries static since s5 doesn't support deep linking.
remove TITLE from readme, not handled properly by github org-ruby
Update org-deck customization info