Fixed content length bug in Echo handler

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/benchmark/httpclient/branches/4.2.x@1499522 13f79535-47bb-0310-9956-ffa450edef68
Added git ignore

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/benchmark/httpclient/branches/4.2.x@1499524 13f79535-47bb-0310-9956-ffa450edef68
Migrated to Gradle for build and execution automation

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/benchmark/httpclient/branches/4.2.x@1499525 13f79535-47bb-0310-9956-ffa450edef68
Run each agent in a separate process

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/benchmark/httpclient/branches/4.2.x@1499526 13f79535-47bb-0310-9956-ffa450edef68