DOC: Update changelog

Author: effigies

Changelog

@@ -28,6 +28,8 @@ References like "pr/298" refer to github pull request numbers.
 2.5.0 (To be decided)
 =====================
 
+Thanks for the test ECAT file and fix provided by Andrew Crabb.
+
 Enhancements
 ------------
 * Add SerializableImage class with to/from_bytes methods (pr/644) (CM,
@@ -39,12 +41,16 @@ Bug fixes
 ---------
 * Handle stricter numpy casting rules in tests (pr/768) (CM)
   reviewed by PM)
+* TRK header fields flipped in files written on big-endian systems
+  (pr/782) (CM, reviewed by YOH, MB)
+* Load multiframe ECAT images with Python 3 (CM and Andrew Crabb)
 
 Maintenance
 -----------
 * Fix CodeCov paths on Appveyor for more accurate coverage (pr/769) (CM)
 * Move to setuptools and reduce use ``nisext`` functions (pr/764) (CM,
   reviewed by YOH)
+* Better handle test setup/teardown (pr/785) (CM, reviewed by YOH)
 
 API changes and deprecations
 ----------------------------