* Minimize re-rendering of 'bulk update users' table
And use ARIA to announce a summary of the bulk update. By using a
checkbox input to represent the activation status, we don't need to
re-render it when it's changed, because the checkbox itself manages that
state.
Re: #1431
* Improve screen reader pronunciation
* fix accesibility and keyboard navigation issues in examples
* fix review comments
* remove redundant aria attributes, remove redundant autofocus
* rework progress bar demo's accesibility
* rework tabs HATEOS example to be more ARIA compliant
* rework tabs _hyperscript example to be ARIA compliant
