[core] add missing license headers. (#1313)

* #1249 missed headers when moving things out of Client.java
* #1242 missed header on a properties file is added
* #1286 missed header on the new pom file

core/src/main/java/com/yahoo/ycsb/ClientThread.java

+/**
+ * Copyright (c) 2010-2016 Yahoo! Inc., 2017 YCSB contributors All rights reserved.
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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. See accompanying
+ * LICENSE file.
+ */
+
 package com.yahoo.ycsb;
 
 import com.yahoo.ycsb.measurements.Measurements;

core/src/main/java/com/yahoo/ycsb/StatusThread.java

+/**
+ * Copyright (c) 2010-2016 Yahoo! Inc., 2017 YCSB contributors All rights reserved.
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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. See accompanying
+ * LICENSE file.
+ */
+
 package com.yahoo.ycsb;
 
 import com.yahoo.ycsb.measurements.Measurements;

postgrenosql/conf/postgrenosql.properties

+# Copyright (c) 2017 YCSB contributors. All rights reserved.
+#
+# 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. See accompanying
+# LICENSE file.
+
 postgrenosql.url = jdbc:postgresql://localhost:5432/test
 postgrenosql.user = postgres
 postgrenosql.passwd = postgres
-postgrenosql.autocommit = true
\ No newline at end of file
+postgrenosql.autocommit = true

tablestore/pom.xml

 <?xml version="1.0" encoding="UTF-8"?>
+<!--
+Copyright (c) 2018 YCSB contributors. All rights reserved.
+
+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. See accompanying
+LICENSE file.
+-->
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
     <modelVersion>4.0.0</modelVersion>