Incorporated pull requests #1305 and #1306.
Restored declaration of 'hidden' class to index file.
Restored h2 in sections for navigation purposes.
Cleaned up index.html.
Updated web UI to a more modern interface while keeping the HTML structure as similar to the original as possible.
New features include:
-Mobile view compatibility
-New light color scheme using primary colors based off Radicale's official colors
-Dialog theme for most sections
-Floating Action Buttons (FAB's) for creating and uploading a new collection
-Commands to edit/delete a collection have become buttons that only show on hover.
-Improved loading screen
-New loading circle with consistent color scheme
-More explanation for dialog text
-Added warning to delete screen
"icon" is standard and used by all modern browsers. Only IE needed
"shortcut icon". Since is it not longer supported and would have needed an
.ico-file, "icon" is the right value for rel.
