There is a bug in tutorial_01_first_tree

run "t01_first_tree_dynamic" program will prompt: could not load library : ./libdummy_nodes.so: cannot open shared object file: no such file or directory.
Line 73 in the  program:
-factory.registerFromPlugin("./libdummy_nodes.so");
+factory.registerFromPlugin("../libdummy_nodes_dyn.so");