Merge pull request #256 from graphitefriction/1-5-docs

migrates portions of the user manual to 1.5
revisions to 1.5.0 release notes & announcement
use bundle exec when calling awestruct; use Asciidoctor master
use https where applicable
load MathJax in footer if page-stem is set
revert test block from migration page
use bundle exec locally
use attribute ref to refer to github.com
add primary class to main content
enable stem on 1.5.0 release announcement
update stylesheet to use default theme from upstream
update README / index page from upstream
additional updates to stylesheet
wrap link label in quotes
upgrades quick ref to 1.5