[1.10.2] Modular Routers - flexible item manipulation with pluggable modules

I actually came up with this idea a few years back when I wrote Bukkit plugins (and implemented it in the Sensible Toolbox plugin).  But then I quit Bukkit and didn't do much of any development until a couple of months ago, when I decided to have a play with Forge modding.  So here it is: Modular Routers.

The idea: one block (the Item Router) and a collection of modules and upgrades which can be installed in said router to manipulate items which pass through the router.  The router has only a single-slot inventory, and any installed modules (up to 9) do something with the buffer - e.g. drop an item into the world, send the item along to a nearby or distant inventory, pull items from an adjacent inventory into the buffer...

Not intended as a replacement for more sophisticated item routing or piping systems but as a complement to them, for example when you want to move items across a room without laying a load of pipes under the floor.  Here's an example use case, for supplying some Botania endoflames with coal:

• Dig a one-block hole and put an item router in it, so it's flush with the ground
  
• Set the router to run only when it has no redstone signal (router has a GUI button for this)
  
• Put a pressure plate on top of the router
  
• Add a Dropper Module to the router and configure it to drop items upwards
  
• Fill the router with coal (manually or perhaps from a hopper or other supply system, maybe even another router with a long-range Sender Mk2 module)
  
• Hey presto - a super-unobtrusive flower feeding system!
  

Much more info at:

• CurseForge: https://minecraft.curseforge.com/projects/modular-routers
  
• Source: https://github.com/desht/ModularRouters
  
• Wiki: https://github.com/desht/ModularRouters/wiki