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.
We had the ng-click on the material-toolbar-tools because on Android it's a convention to be able to click anywhere on the header to open the sidemenu.