Added 'get_new_node' method, so the new obstack contains the correct nodes.
Added 'get_new_node' method, so the new obstack contains the correct nodes.

[r39]

killbug2004/libfirm,libfirm/libfirm,MatzeB/libfirm,jonashaag/libfirm,killbug2004/libfirm,8l/libfirm,libfirm/libfirm,davidgiven/libfirm,davidgiven/libfirm,8l/libfirm,8l/libfirm,jonashaag/libfirm,8l/libfirm,davidgiven/libfirm,8l/libfirm,MatzeB/libfirm,killbug2004/libfirm,8l/libfirm,killbug2004/libfirm,davidgiven/libfirm,MatzeB/libfirm,jonashaag/libfirm,jonashaag/libfirm,MatzeB/libfirm,killbug2004/libfirm,MatzeB/libfirm,8l/libfirm,davidgiven/libfirm,libfirm/libfirm,killbug2004/libfirm,davidgiven/libfirm,davidgiven/libfirm,killbug2004/libfirm,MatzeB/libfirm,jonashaag/libfirm,MatzeB/libfirm,libfirm/libfirm,libfirm/libfirm,jonashaag/libfirm,jonashaag/libfirm