Fixes for latest accessibility audit

After auditing the docs and demos with a few different tools, I found items that needed fixing for accessibility. These include alt text, title attributes, new window warnings and a `lang="en"` attribute on the `<html>` tag. Anything not addressed in this PR has been captured in other issues.
I think there should be two `ng-click`s then....the user has to be able to operate the button itself.