update changelog

CHANGELOG.txt

+Changes In Release 1.3.2
+--------------------------------------------------------------------------------
+
+  * Fixed atom ordering in the GetFrameFromEntity() function in the 
+    structure_analysis.py module.
+  * Fix atom indices generated by CoordGroup::Filter()
+  * small tweaks to lDDT output
+  * small tweaks to molck
+
 Changes In Release 1.3.1
 --------------------------------------------------------------------------------