Make export to html compatible with GitHub and toc-org
Make export to html compatible with GitHub and toc-org

Add new html preprocessors to the org-html-publish-to-html pipeline:
- `spacemacs//toc-org-unhrefify-toc`
- remove the `toc-org` modifications for the TOC
- `spacemacs//org-heading-annotate-custom-id`
- annotate org headings with the indexes that GitHub uses for linking.
  `org-html-publish-to-html` will use them instead of the default
  `#orgheadline{N}`. This way the GitHub links and the
  http://spacemacs.org/ links will be compatible."
- `spacemacs//reroot-links`
- find the links that start with
  https://github.com/syl20bnr/spacemacs/blob/ and end with
  .org{#an-optional-heading-link} (i.e the links between the local org
  files). Change their root to http://spacemacs.org/ so the links will
  point at files located on the site.

*For the "file to file" links to work properly the expor

tsonntag/dotemacs,tsonntag/dotemacs,tsonntag/dotemacs,tsonntag/dotemacs