gitweb: History: blob and tree are first, then commitdiff, etc

gitweb: History: blob and tree are first, then commitdiff, etc

Reorder link display in history to be consistent with other
list displays: log, shortlog, etc.  We now display:

	blob | commitdiff
	blob | commitdiff | diff_to_current

and

	tree | commitdiff

Instead of the old history format where "blob" and "tree"
are between "commitdiff" and "diff_to_current" if present/
applicable.

Signed-off-by: Luben Tuikov <ltuikov@yahoo.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>