open navigation section for current page
toggle class for headings
use classList.toggle
syntax
optimize parameter tracking

* fetch link plus add 'is-active' css-class
* go DOM up to ul and headline
Merge pull request #46 from m5o/navigation-section-is-open

open navigation section for current page
highlight code in readme file
Merge pull request #57 from carlosrberto/master

highlight code in readme file
Merge pull request #54 from freshbooks/master

Add an option, `dryRun` which will make the task exit non-zero if there are missing docs.