Update various libraries' documentation build.

Mostly to use the images and css files under doc/src instead of
doc/html, usually be deleting the settings in order to use the defaults.
Also add 'boost.root' to some builds in order to fix links which rely on
it.

[SVN r63146]

string/doc/Jamfile.v2

@@ -12,6 +12,7 @@ toolset.using doxygen ;
 
 boostbook string_algo : string_algo.xml autodoc 
 	:
+        <xsl:param>boost.root=../../../../..
         <format>pdf:<xsl:param>boost.url.prefix=http://www.boost.org/doc/libs/release/doc/html
 	;