Fix hopelessly out-of-date README.txt.

README.txt

-Installation
-------------
+This is the Drupal 8 development version of FillPDF. Only use this if you are
+using Drupal 8. Otherwise, use the code at https://drupal.org/project/fillpdf.
+This repository has its own issue and pull request queue. Please only use that
+for Drupal 8-related stuff. Otherwise, file an issue at https://drupal.org/project/issues/fillpdf.
 
-This module requires one of several external PDF manipulation tools. You can:
+The setup for this module is essentially the same regardless of Drupal version.
 
-   1. Deploy locally -- You'll need VPS or a dedicated server so you can deploy PHP/JavaBridge on Tomcat or a similar servlet container, or
-   2. Sign up for FillPDF Service, and plug your API key into /admin/settings/fillpdf
-   3. Install pdftk on your server and have that be used for PDF manipulation
-
-For more information, see the full documentation on drupal.org: http://drupal.org/documentation/modules/fillpdf
+See the full documentation on drupal.org: http://drupal.org/documentation/modules/fillpdf