Bump version to 2.2.3, update Readme and Changlog

Change-Id: Ic4928596d72ce3f738a47f112d8064dc63324f56
diff --git a/pom.xml b/pom.xml
index 66de8d1..7eae38d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>de.ids_mannheim.korap.tokenizer</groupId>
     <artifactId>KorAP-Tokenizer</artifactId>
-    <version>2.2.2</version>
+    <version>2.2.3</version>
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>