Give compatibility with Custom Mobs plugin

This would extend the compatibility of denizen with all the Custom Mobs plugins or mobs created by command blocks.
This would also solve this issue because MM offers commands to spawn and remove mobs, with the mobnames argument you can now check for the display name that you can set in the config (I think all the custom mobs plugins offer this feature) : https://github.com/Morphan1/Depenizen/issues/20

I used contains() instead of equalsIgnoreCase to check for the name because some plugins could add informations to the mob's name like the level or the health.

I tested this in local and should work fine.
I'm not sure of how to do pull request so i copied the new code from my local file in the file here, but everything should be in the right place :)
Update KillListenerInstance.java
Update CommandRegistry.java
Update CommandRegistry.java
Add dCore link to the readme

Also update the Depenizen link and the tutorial vid link
Fix annoying dInventory debug bug

No, we're not trying to adjust the property, silly.
Allow empty alias list for command scripts

Oops.
Add slot numbers to "drags in inventory" context

For #859
Stop workbenches from being opened by tags

This is a somewhat error prone system if you don't know what you're
doing. I'm not sure how to handle sub-tag exceptions after the
dInventory returns null... Or if that should even be done...
@mcmonkey4eva ?
Fix dNPC inventories

In some cases, dNPC wasn't properly registering to the registry... Bad!
Fix build error, formatting

Careful, @o0ower0o...