Update license.txt

Update year from 2012->2016

Author: popzip

license.txt

@@ -1,4 +1,4 @@
-Copyright 2012 MarkLogic Corporation
+Copyright 2016 MarkLogic Corporation
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -10,4 +10,4 @@ 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.
+limitations under the License.