Bootstrap for embedded server based on classic I/O

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk@1597549 13f79535-47bb-0310-9956-ffa450edef68
Use new embedded server for integration tests

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk@1597550 13f79535-47bb-0310-9956-ffa450edef68
Cleanups
Use ExceptionLogger in HttpAsyncService, HttpAsyncRequester and HttpAsyncRequestExecutor