INT-3461: Add `rometools` Dependency for SF 4.1

JIRA: https://jira.spring.io/browse/INT-3461

To test it: `gradlew :spring-integration-http:testAll -PspringVersion=4.1.0.BUILD-SNAPSHOT`

INT-3461: Add CP condition for `rometools` into the `HttpRequestHandlingEndpointSupport`

INT-3461: Add CLASSPATH check for `RequestEntity` to determine the SF 4.1

Conflicts:
	build.gradle

Resolved.