body classes handling - upgrade to D6 ...

I use garland as a base theme for mine.
I didn't actually applied these to changes to garland theme, but to my own, in order to get more flexibility to layout.
But I think the patch I provide here shouldn't change any behavior of garland theme, "out of the box"; anyway it might be of some use for other "end-users" of garland, so here are my notes:

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Garland's function 'phptemplate_body_class($left, $right)' looks like a reminiscence of D5.
In D6, to provide body element class attribute to page.tpl.php, 'template_preprocess_page()' initialises $vars['body_classes'] instead.

Two differences:

1. phptemplate_body_class() returns the full attribute string,
   while $body_classes holds the attribute value.
   -> page.tpl.php small change
2. the classes names have changed
   '' -> 'no-sidebars',
   'sidebars' -> 'two-sidebars',
   'sidebar-left' -> 'one-sidebar sidebar-left',
   'sidebar-right' -> 'one-sidebar sidebar-right',

   So we need to change our css selector 'sidebars',
   in style.css and print.css

         sed -i 's/\.sidebars/.two-sidebars/g' style.css
         sed -i 's/\.sidebars/.two-sidebars/g' print.css
   

Two new layout classes are then available: 'no-sidebars', 'one-sidebar', and many others, e.g. 'node-type-*' .

Oh ... reviewing the patch I saw a small typo in print.css line 22:
'sideber-left' ...
I don't know the consequences yet, so I left it in place.

HTH