update gson

.idea/libraries/gson.xml

@@ -1,11 +1,11 @@
 <component name="libraryTable">
   <library name="gson">
     <CLASSES>
-      <root url="jar://$PROJECT_DIR$/lib/gson-2.3.jar!/" />
+      <root url="jar://$PROJECT_DIR$/lib/gson-2.3.1.jar!/" />
     </CLASSES>
     <JAVADOC />
     <SOURCES>
-      <root url="jar://$PROJECT_DIR$/lib/src/gson-2.3-sources.jar!/" />
+      <root url="jar://$PROJECT_DIR$/lib/src/gson-2.3.1-sources.jar!/" />
     </SOURCES>
   </library>
 </component>

lib/required_for_dist.txt

@@ -16,7 +16,7 @@ freemarker.jar
 httpmime-4.3.6.jar
 ecj-4.4.jar
 groovy-all-2.3.9.jar
-gson-2.3.jar
+gson-2.3.1.jar
 guava-17.0.jar
 hamcrest-core-1.3.jar
 hamcrest-library-1.3.jar