Add return code for Kafka::produce; Free payload when rkq is full
Initial 0.8 producer support.

This is work in progress but functional and ready for testing.
Added named configuration property support matching the standard Apache Kafka properties.
rd_kafka_set_logger() is now per rd_kafka_t handle.
Dont require individual builds of each example program.
Updated documentation.
Error out on NULL topics in rd_kafka_topic_new().
Proper DESTDIR usage in install target
Merge pull request #12 from ZhuYouzhi/master

Add return code for Kafka::produce and free message payload memory in rd_kafka_example when queue is full
Let non-broker threads trigger leader queries.
Re-delegate all affected topic+partitions when a broker fails (issue #14)
If new topic is unknown, requery brokers to find a leader (issue #16)
Added broker state name printouts to rd_kafka_dump()
Constified rd_kafka_name() argument
Use proper define for RD_POLL_NOWAIT
Indent fix
rdkafka_example: dump rdkafka internal state info to stdout on SIGUSR1
rdkafka_example: added logger callback and -d command line argument to enable debugging.
rdkafka_example: Proper SIGINT handling
Merge branch '0.8-wip' into master.