[MINOR] CSS & HTML fun

[MINOR] CSS & HTML fun

This patch makes stats page about 30% smaller and
"CSS 2.1" + "HTML 4.01 Transitional" compliant.

There should be no visible differences.

Changes:
 - add DOCTYPE for HTML 4.01 Transitional
 - add missing </ul>
 - remove cols=, AFAIK no modern browser support this property and
   it prevents validation to pass.
 - remove "align: center": there is no such property in css. There is
   however "text-align: center" but it is definitely not what we would
   like to see here.
 - by default align .titre to center
 - by default align .td to right
 - remove all align=right, no longer necessary
 - add class=ac (align center): shorter than "align=center" and use it when
   necessary
 - remove nowrap from td, instead use "white-space: nowrap" in css

Now stats page passes W3C validators for HTML & CSS. We may consider adding
"validated" icons from www.w3.org. ;)