Update themes for Asciidoctor 1.5

Resolves #52
Upgrade to Asciidoctor 1.5.0-rc.5
Reformat html code
Reformat json code
Reformat js code
Add Grunt and Jasmine to automate packaging and testing
Add Travis CI
Add Grunt as dev dependencies
Add project health
Add grunt-cli and simplify travis conf
Change namespace to asciidoctor.chrome
Fix bugs and move vendor js to vendor directory
WIP Add custom CSS/JS
Allow users to add custom stylesheet and JavaScript

Ref #31 and #39