Ore Remover - Block Changer

Who said you cannot remove ores or blocks from an old world?
With this plugin, you can remove ores and blocks from an existing world without creating(or editing it with some sort of program) a new one.

Cool features

Remove blocks just from just a world. You can choose which one from the config.
Settable radius (in chunks) and speed. So you don't make your server or your players crash.
Placed blocks in already edited chunks won't disappear! So your players will not lose materials!
It's free! You don't need to pay anything to use this plugin!

How does this work?
When the player moves the plugin will search for blocks in the chunks around the player (using the radius that you defined) and turn them to other blocks.
These 2 actions (search and replace) are divided into 2 different tasks (one is async and one is sync).

Tutorial
Here is the default config!
replace:
- air:
- iron_ore
- diamond_block
size: 1 #in chunks
delay: 5 # in ticks
blocksperdelay: 500
worlds:
- "world"
- "ores_world"

The list "worlds" contains the name of the worlds where this plugin should be on. (Is case sensitive)
The "size" is how many chunks around the player shold be processed by the plugin. The default is one. If your server doesn't have a LOT of ram you should NOTmake this more than 3
The "delay" is how often should the plugin continue to change the blocks
The "blocksperdelay" is how many blocks can the plugin process at most every time. Note that, as a sync task, your server will freeze if it tryes to load too many blocks. If all the blocks has not been processed the plugin will continue to replace the block after the delay you specified before.
If you didn't understand a word of what I just said, just be aware that less delay equals faster but requires a lot of resources.
Same thing with "blocksperdelay" but higher numbers is the fastest and costy one.

To add a block to change, type "- to:" then "- from" with the same format of the default config

Warnings
Setting a too high radius the server or even the game of the player may crash. Decide your radius wisely (The default one is 1)! (Not that try to edit unloaded chunks will throw a lot of exceptions. The chunks wont unload anyway if the change is going on but this wont work if they aren't loaded before)

This plugin is still in beta and may have unexpected behaviors.
Use this at your own risk.
We advise you to keep backups of the worlds and report bugs or glitch as soon as possible.

ALSO
If you test the plugin in other versions(Not 1.8.8) please tell me if they work so I can add them to the tested versions.