Combine poole, lanyon and custom CSS.

- Load a single file from HTML
- Avoid multiple declarations for same selectors.
Delete unused/unnecessary templates.
CSS changes for related posts/section list styling
Standardize the grey usage to #9a9a9a
"summary" and "sectionlist" short codes
Reduce bottom margin

Top had been reduced earlier. So keeping it in proportion.
Use the new shortcodes/summary in index.html and list.html