create necessary files under subdirectory ExText

In the new 0.7000 version, the extensions can be compiled seperately with the Gtk support. You can put our extension anywhere in the filesystem. However, it's convient to create a subdirectory ExText under the root of source tree of Perl-Gtk.

You need the following files to build a Gtk object.

ExText.pm

Create a module for Gtk object. The easiest way is to copy it from other module and modify it to fit your classes. You can get one by using the following steps.