This is a stable release, an optional but recommended update for both mainnet
and testnet.

Performance optimizations in trimming of the derived tables to speed up
blockchain download.

Trimming frequency can now be modified per table by setting a frequency
modifier property nxt.trimFrequencyMultiplier.<tablename> for that table.

The default log file name has been changed from logs/nxt.log to logs/nxt.0.log
and up to 10 log files are now kept.

Added a checkpoint after the last hardfork block.

Blacklist nodes running versions older than 1.12.1.

