CAMEL-5459: Added option closeFolder to mail consumer to allow end users to control if folder should be closed after poll or not. Thanks to Fabio Berchtold for the patch.

git-svn-id: https://svn.apache.org/repos/asf/camel/branches/camel-2.10.x@1441880 13f79535-47bb-0310-9956-ffa450edef68