The commitdiff will be generated against the first parent, and the
diff page also gets the benefit of repo.defbranch.
Cleaned up some bad whitespace in cgit.h while at it.
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
A link is added next to each parent of a commit, leading to the new
diff-functionality in ui-diff.c.
Also added support for a path-parameter to filelevel diffs accessed via the
diffstat.
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
