Issue #189: Porting Admin Menu to Backdrop. Removing Toolbar.
Issue #189: Include top-level tabs as children in admin menu.
Issue #189: Incrementing update number to enable admin menu.
Merge pull request #207 from quicksketch/189/admin_menu

Issue #189: Porting Admin Menu to Backdrop. Removing Toolbar.
Issue #189: Adding safety check to Admin Menu update.
Issue #117: Provide Backdrop-unique constants for identifying Backdrop version.
Issue #117: Updating Backdrop versions in newly added modules.
Issue #1913692 by mgifford: Convert Seven to HTML5.
Issue #117: Fixing tests affected by new Backdrop version constants.
Issue #117: Updating identifiers to use 'Backdrop CMS' for clarity.
Merge pull request #216 from quicksketch/117/backdrop-version

Issue #117: Identify Backdrop version and distinguish it from Drupal 8.x.
Issue #1179764 by mjohnq3, mbrett5062, tim.plunkett: Convert Bartik to HTML5.
Issue #2011578 by mortendk, tlattimore, Cottser, soulston: Markup for Stark's page.html.twig + maintenance-page.html.twig.
Issue #1190206 by cosmicdreams: Convert taxonomy-term.html.twig to HTML5.
Followup: Issue #1913692 by mgifford: Convert Seven to HTML5.
Return the profile selection minimal to its hidden state.
Merge pull request #226 from jenlampton/117-installer-fix

Return the profile selection minimal to its hidden state.
Merge pull request #215 from hellomrcat/235

Issue #1913692 by mgifford: Convert Seven to HTML5.
Merge pull request #218 from jenlampton/html5-bartik

Issue #200: Backport Converting Bartik to HTML5.
Merge pull request #213 from hellomrcat/233

Issue #1190206 by cosmicdreams: Convert taxonomy-term.html.twig to HTML5.