travis-ci.org integration
(cherry picked from commit 2103defc231585fc8a3436a8f8d05eb6d13976da)
Merge pull request #8 from eugpermar/0.7

Created a small c++ librdkafka produce wrapper.
Added conf.producer.max_outq_msg_cnt: allows the application to limit the outgoing message queue size.
Fix: Makefile doesn't contained all the headers in HDRS variable