Migrated to Gradle build

This commit migrates from a Maven-based build system to a Gradle-based
one. Changes include:

- Removed archetype & parent
- Renamed core, support, test, security and xml directories to
  spring-ws-core, spring-ws-test, spring-ws-security, spring-xml
  respectively.
- Moved samples to separate project
  (https://github.com/spring-projects/spring-ws-samples)
Upgraded to gradle wrapper 1.9
Wrong check if logger is enabled in WebServiceTemplate.logResponse method.
Merge pull request #9 from apechinsky/wrongLoggerCheck

Wrong check if logger is enabled in WebServiceTemplate.logResponse method.
Return null URI for null Destination

JmsTransportUtils.toUri now returns null for null destination
parameters.

Issue: SWS-848
Resolved NullPointerException

When the payload is null, the PayloadRootSmartSoapEndpointInterceptor
does not throw an exception anymore.

Issue: SWS-857
AxiomUtils.toEnveloper now using StAXUtils

Previously, AxiomUtils.toEnvelope() constructed its own XMLInputFactory
for creating a XMLStreamReader. Now we use Axiom's StAXUtils instead,
thus allowing users to use the standard Axiom mechanisms for setting
STAX properties etc.

Issue: SWS-851
Javadoc
Updated tutorial to SWS 2.1

Updated tutorial to use Spring-WS 2.0.1, specifically JDOM 2.

Issue: SWS-854
Corrected issue tracking section. Copy-pasta said Spring Scala should have said Spring Web Services.
Merge pull request #10 from NVolcz/master

Corrected issue tracking section.
WSMessageSender based on ClientHttpRequestFactory

Introduced an implementation of WebServiceSender that wraps
ClientHttpRequestFactory, as found in Spring 3.

Issue: SWS-859
Fixed dependencies for spring-ws-test
Merge branch 'master' of github.com:SpringSource/spring-ws
Make future time to live configurable

Added timeToLive property to the Wss4jSecurityInterceptor.

Issue: SWS-862
Configurable PKIXBuilderParameters for XWSS

Allow customization of the PKIXBuilderParameters by having a factory
method for it. Also added a revocationEnabled flag, defaulting to false.

Issue: SWS-853
Added template method for NoEndpointFoundException

Introduced handleNoEndpointFoundException to allow for customization in
subclasses.

Issue: SWS-850
Removed Token signing section

Removes section that mentions the special "Token" keyword in binary
signature signing, since that feature is no longer supported as of WSS4J
1.6

Issue: SWS-842
Added test for XSD attributes

Added additional tests for inlining XSD attributes.

Issue: SWS-861
Added test for XSD attributes

Added additional tests for inlining XSD attributes.

Issue: SWS-861