Creates a new tree store as with @n_columns columns each of the types passed in. Note that only types derived from standard GObject fundamental types are supported. As an example, <literal>gtk_tree_store_new (3, G_TYPE_INT, G_TYPE_STRING, GDK_TYPE_PIXBUF);</literal> will create a new GtkTreeStore with three columns, of type <type>int</type>, <type>string</type> and GdkPixbuf respectively.