Update to allow the project to compile in Netbeans, as per:

http://stackoverflow.com/questions/314572/bug-in-eclipse-compiler-or-in-javac
Also added license files, for building into JAR file

licenses/gson-license.txt

@@ -0,0 +1,13 @@
+Copyright (c) 2008-2009 Google Inc. 
+
+Licensed under the Apache License, Version 2.0 (the "License"); 
+you may not use this file except in compliance with the License. 
+You may obtain a copy of the License at 
+
+  http://www.apache.org/licenses/LICENSE-2.0 
+
+Unless required by applicable law or agreed to in writing, software 
+distributed under the License is distributed on an "AS IS" BASIS, 
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+See the License for the specific language governing permissions and 
+limitations under the License.