Using Jackson 2 HttpMessageConverter if Jackson 2 is available in classpath
Merge branch 'jackson2httpinbound' of https://github.com/bijukunjummen/spring-integration into INT-2312

Conflicts:
	spring-integration-http/src/main/java/org/springframework/integration/http/inbound/HttpRequestHandlingEndpointSupport.java
Apply Biju Kunjummen commit