Update release notes for 1.4.7 release.
pyglet 1.4.7
-Bugfix release
+Bugfix and small improvement release
Bugfixes
--------
- Allow creation of non-power-of-two compressed Textures. (#78)
+Improvements
+------------
+- Windows: Add support for `Desktop Window Manager` composition for smoother rendering.
+- TextureAtlases allow a single pixel border to avoid rendering artifacts.
+
pyglet 1.4.6
Bugfix release
