[index-html-split] Added RevealCK.path_to
[index-html-split] Extracted index_head.html.erb from index.html.erb

* Scope gains a :config

* Scope gained a :config so that it could render ERB while rendering
  ERB.
[index-html-split] Extracted index_body.html.erb from index.html.erb
[index-html-split] Extracted index_script.js.erb from index_body.html.erb
[index-html-split] Added RevealCK::Render::IndexHtmlMaker
[index-html-split] Config is now globally shared while rendering

We render:

1. index.html.erb
2. Slides

And we now use a shared Scope that could provide access to a shared
config.
[index-html-split] Added ability to reference config.data

This naturally falls out of consolidating the rendering scopes and
making sure the consolidated scope has access to the common config.
You can now put 'data' into your config.yml for reference

Merge branch 'index-html-split' into upcoming

* index-html-split:
  [index-html-split] Added ability to reference config.data
  [index-html-split] Config is now globally shared while rendering
  [index-html-split] Added RevealCK::Render::IndexHtmlMaker
  [index-html-split] Extracted index_script.js.erb from index_body.html.erb
  [index-html-split] Extracted index_body.html.erb from index.html.erb
  [index-html-split] Extracted index_head.html.erb from index.html.erb
  [index-html-split] Added RevealCK.path_to