JCRVLT-54 - [vault-rcp] Allow single task retrieval
- add RcpTaskManager#getTask method and impl
- enhanced RcpServlet to check whether request suffix is present and use that to fetch task

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/commons/filevault/trunk@1610481 13f79535-47bb-0310-9956-ffa450edef68