XWiki configuration files shouldn't depend on a given environment

The xwiki.cfg file contains pathnames valid in Windows only (moreover, particular to the developer's machine), like c:/Program Files/ATT/GraphViz/bin/dot.exe or c:/Program Files/Apache Software Foundation/Tomcat 5.0/webapps/openlaszlo/xwiki/.

When building or installing XWiki, the xwiki.cfg file shouldn't contain any environment-dependent configurations (these should be set by the user depending on his environment).