Update Installation steps on module page

Current text

1. Module can be installed via the standard Drupal installation process.
2. Go to the "Manage fields" page for an entity.
3. Add a new field of "Display mode" type.
4. You can then adjust the field settings (e.g. default value or excluded modes).
5. After saving the field, go to the "Manage form display" tab.
6. Select the desired widget for the display mode field and save the form.
7. Go to "Manage display" and find your existing entity reference field.
8. Choose "Selected display mode" format and save the form again.
9. That's it. Just edit the entity and select different displays.

New steps

1. Module can be installed via the
[standard Drupal installation process](http://drupal.org/node/1897420).
2. Go to the "Manage fields" page for an entity.
3. Add a new field of "Reference" type.
4. Select "Display mode" in the options page.
5. You can then adjust the field settings (e.g. default value, excluded or
included modes).
6. After saving the field, go to the "Manage form display" tab.
7. Select the desired widget for the display mode field and save the form.
8. Go to "Manage display" and find your existing entity reference field.
9. Choose "Selected display mode" format and save the form again.
10. That's it. Just edit the entity and select different displays.