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
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.
Describe Kafka protocol version support for different branches.