New Features:

Added Spawner breaking and placing, that can be customizable;
Added commands for easier customization;
Cost and cost increase can be change for individual entities separately.

New Commands:

Added /spawnermeta or /sm to view possible operations;
/sm update - to update the plugin without restarting the server
/sm get - to get spawner(s) with specific entity
/sm cost - to configure spawner upgrading cost
/sm increase - to configure spawner upgrading cost increase
/sm breaking - to configure spawner breaking