Optimize nimitz file store

The "Nimitz" file format has been improved in many ways. All columns to store block tile data, such as chest contents and sign text, are now a single column to reduce storage usage for all those extra columns. War now checks all blocks when restoring to see if they have been changed before sending out client updates. Each batch reset operation does not cause the file to be loaded a separate time. The database does not hold AIR blocks anymore. Instead, blocks that do not exist in the database but within the zone bounds are assumed to be AIR.
This also adds configuration options RESETBLOCKS to disable automatic resets.
Closes #706