closes https://github.com/assimp/assimp/issues/1102: update CHANGES file.

CHANGES

@@ -2,7 +2,40 @@
 CHANGELOG
 ----------------------------------------------------------------------
 
-3.2.1 (2016-10-01)
+3.3.1 (2016-07-08)
+
+FIXES/HOUSEKEEPING:
+    - Setup of default precision for 17 exporters
+    - Fix xcode project files
+    - Fix BlenderTesselator: offsetof operator
+    - Invalid version in cmake file
+    - Update pstdint.h to latest greatest
+
+
+3.3.0 (2016-07-05)
+
+FEATURES:
+    - C++11 support enabled
+    - New regression-test-UI
+    - Experimental glTF-importer support
+    - OpenGEX: add support for cameras and lights
+    - C4D: update to latest Melange-SDK
+    - Add a gitter channel
+    - Coverity check enabled
+    - Switch to <...> include brackets for public headers 
+    - Enable export by pyAssimp
+    - CI: check windows build
+    - Add functionality to perform a singlepost-processing step
+    - many more, just check the history
+
+FIXES/HOUSEKEEPING:
+    - Fix of many resource leaks in unittests and main lib
+    - Fix iOS-buildfor X64
+    - Choosing zlib manually for cmake
+    - many more, just check the history
+
+
+3.2.1 (2016-010-10)
 
 FEATURES:
   - Updated glTF exporter to meet 1.0 specification.
@@ -17,7 +50,6 @@ ISSUES:
   - void* in ExportData for accessor max and min.
 
 
-
 3.2.0 (2015-11-03)
 
 FEATURES: