New features and commands:

Remade spawner location file with. This will slightly affect only those who have enabled stacking, as previously each stacked spawner counted towards player owned spawner limit, but with this update stacked spawners will only count as one.

Added price number formatting.
Added command aliases.
Added permissions for stacking and ownership limit.

Added new command to allow players to view all their placed spawners.
Default command - /spawnerlocations

Added new command to add, remove, clear and view trusted players. Trusted player will be able to manipulate with trustee's spawners (options defined in configuration file) even if ownership options are disabled.
Default command - /spawnertrust

Added timer to check for invalid spawner, to improve server performance.

Fixes:

Fixed errors when placing and breaking spawners.
Fixed holograms not disappearing.