Bump version to 0.7.5 and add CHANGELOG.md

Change-Id: Iae7069e3e8d00e6944198a651f8767a109226987
diff --git a/setup.py b/setup.py
index 9fc5a97..2f195bf 100644
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@
 
 setup(
     name="KorAPClient",
-    version="0.7.1.9000",
+    version="0.7.5",
     author="Marc Kupietz",
     author_email="kupietz@ids-mannheim.de",
     description="Client package to access KorAP's web service API",