xml nodes now store the location they were parsed from; invalidbuildexceptions now...

xml nodes now store the location they were parsed from; invalidbuildexceptions now required a location of the error; don't allow modules to process xml until all modules are created; don't allow libraries, defines, includes, etc to process xml until all modules have processed; don't allow module to link against itself or a non-existant module; don't allow library to specify non-existant module;

svn path=/branches/xmlbuildsystem/; revision=12879