Change boost.css to set the text colour as it sets the background colour.

Also mark some reverted documentation changes as merged.

Merged revisions 51043-51044,53553,53555 via svnmerge from 
https://svn.boost.org/svn/boost/trunk

[SVN r53684]

boost.css

@@ -25,6 +25,7 @@ BODY
 {
     FONT-SIZE: 100%;
     BACKGROUND-COLOR: #ffffff;
+    COLOR: #000000;
 }
 PRE
 {