Use interface fun instead of direct #group access

BugzID: 13487

Conflicts:
	src/chttpd_view.erl
Return body timing in response header

Conflicts:
	src/chttpd.erl
Respond politely with 404 if show/list/update is missing

BugzID: 14105
DDoc is a #doc{} not a {[]}

BugzID: 17515