Undead Armies

- Changed the logic behind mining, the mining task is more efficient now but the undead mobs are slightly worse at breaking blocks than before (it would seem like). I will try to fix this later.
- Added new setting called "unbreakable" which makes the mobs ignore blocks with block hp above a certain number 
- Added a way to set custom block hp for each block (Wiki page will be added after proper release but for now here is an example for setting all chests and dirt to have a block hp of 100:
```
{
{{minecraft:chest}{100}} 
{{minecraft:dirt}{100}}
}
```