- made compare and commit range pages more consistent with other commit diff pages
- removed mergerly, closes#4665. Old diff2way is replaced by new diffs with
side-by-side mode.
- cleanup button behaviour on compare page. Added help text and
generally improved UX
- switched file-diffs to compare page with file filter. Part of #4000
- added collapse/expand commits buttons in compare views.
Before we used to use JSON data to map the nodes to json and fill in
metadata. Now we use rendered parts of html. This is nicer for caching as
it would allow us to replace the view with cached tree and then after ajax load
replace it again with cached with metadata. On the next request we'll
get the cached with metadata and thus we can skip entirely second
ajax call for metadata.
This is part of #4083