Add JdbcOperationsSessionRepository

This commit provides implementation of SessionRepository based
on Spring's JdbcOperations interface.

@EnableJdbcHttpSession annotation is provided to ease the
configuration, together with spring-session-jdbc BOM and schema
creation scripts for all major databases.

Fixes gh-364

samples/httpsession-jdbc/src/integration-test/groovy/sample/AttributeTests.groovy

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2014-2016 the original author or authors.
+ *
+ * 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.
+ */
+package sample
+
+import geb.spock.*
+import sample.pages.HomePage;
+import spock.lang.Stepwise
+import pages.*
+
+/**
+ * Tests the CAS sample application using service tickets.
+ *
+ * @author Rob Winch
+ */
+@Stepwise
+class AttributeTests extends GebReportingSpec {
+	def 'first visit no attributes'() {
+		when:
+		to HomePage
+		then:
+		attributes.empty
+	}
+
+	def 'create attribute'() {
+		when:
+		createAttribute('a','b')
+		then:
+		attributes.size() == 1
+		attributes[0].name == 'a'
+		attributes[0].value == 'b'
+	}
+}