private void parsePackageLine(String defPackage) {
        root.setPackage(defPackage);
        root.setComment(comment);
        comment = "";
    }
Parses one line from def-file and adds it to the tree.
TODO: Method too long!

@param root     The root CNode in the tree.
@param line     A line from the def-file.
@param nd       A NormalizedDefinition object
@throws IllegalArgumentException upon error in line.
configgen/src/main/java/com/yahoo/config/codegen/DefParser.java