am f5cbe002: Merge "docs: update template and css for android u Add a custom...

am f5cbe002: Merge "docs: update template and css for android u Add a custom version of docpage.cs to the droiddoc template, because it adds a good deal of custom design and behavior (instead of updating the doclava version of the file). Add CSS for next/previous link

* commit 'f5cbe002':
  docs: update template and css for android u Add a custom version of docpage.cs to the droiddoc template, because it adds a good deal of custom design and behavior (instead of updating the doclava version of the file). Add CSS for next/previous links in android u lessons and revise style for download button.