Using multi-faceted strategy to better resolve UUIDs, and do it faster.
Fixed dispensers putting fluids in a neighboring claim.
Automatically deleting claims for worlds which no longer exist.
Streamlined visualization code, hopefully will reduce or eliminate weird
visualizations for VERY big land claims.
Removed option to disallow un-claiming land in creative mode.
Better default for last login date for new players or players who've had
their data deleted or lost.
Rewrote and retested parts of the plugin to use UUIDs instead of player
names to uniquely identify players. Added data migration code to
convert old data to the new (UUID) format.
