INT-1132: Rescheduling Support for DelayHandler

- Add support for DelayHandler to reschedule persisted Messages on startup via 'implements ApplicationListener<ContextRefreshedEvent>' as late as possible
- Change DelayHandler dependency to MessageGroupStore
- Add required DelayHandler.messageGroupId property
- Make registered by SI-namespace TaskScheduler as default for DelayHandler
- Remove 'required' from delayer xml-attribute 'default-delay' as redundant
- Additional refactoring & polishing around <delayer>
- Polishing delayer's Tests
- Tests for 'rescheduling'
- Integration test for 'rescheduling' with JdbcMS

INT-1132: add 'initializingLatch' to DelayHandler

INT-1132: additional polishing

INT-1132: add LIFO JMS polling test-case

INT-1132: Changes according to PR comments

INT-1132: Changes according to PR comments 2

Polishing

Remove blocking calls from tests.

spring-integration-groovy/src/main/resources/org/springframework/integration/groovy/config/spring-integration-groovy-2.2.xsd

@@ -7,7 +7,7 @@
 	elementFormDefault="qualified" attributeFormDefault="unqualified">
 
 	<xsd:include
-		schemaLocation="http://www.springframework.org/schema/integration/scripting/spring-integration-scripting-core-2.2.xsd" 
+		schemaLocation="http://www.springframework.org/schema/integration/scripting/spring-integration-scripting-core-2.2.xsd"
 		/>
 
 	<xsd:import namespace="http://www.springframework.org/schema/integration" schemaLocation="http://www.springframework.org/schema/integration/spring-integration-2.2.xsd" />
@@ -53,7 +53,7 @@
 				<xsd:element ref="integration:poller" minOccurs="0"
 					maxOccurs="1" />
 			</xsd:all>
-			<xsd:attributeGroup ref="integration:inputOutputChannelGroup" />
+			<xsd:attributeGroup ref="integration:inputOutputChannelGroupWithId" />
 			<xsd:attribute name="customizer" type="xsd:string">
 				<xsd:annotation>
 					<xsd:documentation>