Do not hard-code site-visible message strings in skin files

Text strings like "Copyright", "Published", and "Search" are hardcoded into skin files like site2xhtml.xsl. When creating web sites in languages other than English the web developer is forced to create local versions of these skin files with the appropriated translations.

Instead, the DTD for the skinconf.xml should be improved to allow these translations to be specified in this file. This would make Forrest much easier to use.