Fixed various broken links, resolved duplicate ID issues, and re-added a missing image.
Merge pull request #2916 from EricDunsworth/v3.1-broken-link-fixes

Fixed various broken links, resolved duplicate ID issues, and re-added add a missing image.
Tabbedinterface: removed enter key focus of tab panels
Removed all Enter key events from tabs
Tabbed interface: aria-live toggle for cycle on/off
gh-pages