Added TileEntityCache to improve performance overall with new config.

Whenever a TileEntity ticks, if it hasn't been seen before, a new
TileEntityCache will be created with the data found in config. For each
new tick, the te config data will be accessed from the cache to avoid
performance issues.
If you modify the config, you need to reload by running '/cauldron reload'. This
will update the TileEntityCache so it works immediately.

* added caching for entity immediate despawn checks.