Removed #executeMultiple from FutureRequestExecutionService

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1491801 13f79535-47bb-0310-9956-ffa450edef68
Fixed client config example

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1491802 13f79535-47bb-0310-9956-ffa450edef68