- Unified/Inline Diff-View Selectable

- User profile un/follow
- List user's followers/following

I've mostly duplicated the dropdown code from repo/home.tmpl, which
basically only required a change to the URL. This could probably be
broken out into something more modular.

This does not change any content and generated gogs.css is still the same.

Most commit in Git are expected to follow standard of single header line,
followed by description paragraphs, separated by empty line from previous block.

Previously Gogs were treating everything as single header. Now we are trying to
render only first line as header, but following lines (description chunks) as a
verbatim.

With grey SHA1 labels, we should consider having also more subtle strips on
commits list. As current strips blend too much with grey SHA1 labels and top
bar, making hard to distinguish headers from content.

This removes remains from old design, that was not cleaned by previous #2068 PR.

Otherwise the fix will be overwritten by next _octicons.less update.

This is follow-up for 22b0dfbb35.