This is more inline with way GitHub looks like and feels much more natural and
in style with rest of the interface.

Instead using own ellipsis, uses Semantic UI fixed single line table which
effectively applies ellipsis to all overflowing table cells.

NOTE: File list cannot use colspan="2" for 1st "Last commit" elements,
otherwise layout breaks with fixed table.

- copy link button: #1396, #1168, #1668,
- synxtax highlight: #1712, #1549, #1315, #670
- z-index: #1942