Do not throw IOException from NHttpClientConnectionManager#routeComplete

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpasyncclient/trunk@1479144 13f79535-47bb-0310-9956-ffa450edef68
Redesigned minimal HttpAsyncClient implementation

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpasyncclient/trunk@1479145 13f79535-47bb-0310-9956-ffa450edef68