Toc: Pass errors if no atx headers are processed.

Fixes issue #102
Merge pull request #103 from fmoralesc/patch-1

Toc: Pass errors if no atx headers are processed.
Force syntax highlighting on buffer reload
Update support for syntax highlighting code blocks

Fix problem where highlighting is lost on buffer reload.

* origin/pr/93/head:
  Force syntax highlighting on buffer reload
Merge remote-tracking branch 'origin/master' into run

* origin/master:
  Toc: Pass errors if no atx headers are processed.
Don't highlight standalone parentheses

Remove mkdURL from mkdNonListItem contents, since it should only be used
after an brackets for the link text.
Merge branch 'url-hilite' into run

* url-hilite:
  Don't highlight standalone parentheses