title: Drupal module: create a text format
body: <p>I've created a module which defines a new <em>text format filter</em>.<br>
  Now I want to define a <em>text format</em> using this new filter, directly from module php. Drupal Administrator can do this manually from <code>admin/config/content/formats/add</code> admin page, but I want to avoid this step. What do I need to add to <code>my_dmodule.module</code>?</p>