Maintenance release

Default changes

• Change default queue.buffering.max.kbytes and queued.max.message.kbytes to 1GB (#1304)
• win32: Use sasl.kerberos.service.name for broker principal, not sasl.kerberos.principal (#1502)

Enhancements

• Default producer message offsets to OFFSET_INVALID rather than 0
• new nuget package layout + debian9 librdkafka build (#1513, @mhowlett)
• Allow for calling rd_kafka_queue_io_event_enable() from the C++ world (#1483, @akhi3030)
• rdkafka_performance: allow testing latency with different size messages (#1482, @tbsaunde)

Fixes

• Improved stability on termination (internal queues, ERR__DESTROY event)
• offsets_for_times() return ERR__TIMED_OUT if brokers did not respond in time
• Let list_groups() return ERR__PARTIAL with a partial group list (#1508)
• Properly handle infinite (-1) rd_timeout:s throughout the code (#1539)
• Fix offsets_store() return value when at least one valid partition
• portability: rdendian: add le64toh() alias for older glibc (#1463)
• Add MIPS build and fix CRC32 to work on big endian CPUs (@andoma, closes #1498)
• osx: fix endian checking for software crc32c
• Fix comparison in rd_list_remove_cmp (closes #1493)
• stop calling cnd_timedwait() with a timeout of 0h (#1481, @tbsaunde)
• Fix DNS cache logic broker.address.ttl (#1491, @dacjames)
• Fix broker thread "hang" in CONNECT state (#1397)
• Reset rkb_blocking_max_ms on broker DOWN to avoid busy-loop during CONNECT (#1397)
• Fix memory leak when producev() fails (#1478)
• Raise cmake minimum version to 3.2 (#1460)
• Do not assume LZ4 worst (best?) case 255x compression (#1446 by @tudor)
• Fix ALL_BROKERS_DOWN re-generation (fix by @ciprianpascu, #1101)
• rdkafka-performance: busy wait to wait short periods of time