[Feature Request] Add Paperclip, Spigot BuildTools and custom jar support

[mdcfe]

Add support for Paperclip to always get an up-to-date version of PaperSpigot and for BuildTools to be able to compile the chosen version of either CraftBukkit or Spigot without relying on an external build server. A drop down box on the setup page might be a good way to do this, and would mean we can add support for other servers like Sponge (Vanilla/Forge) and Cauldron at a later date.

(node-temp might be useful for BuildTools.)

[gmemstr]

Need to also move away from the request module because currently it doesn't indicate when the file is downloaded fully.

[jaredallard]

@gmemstr Nothing will, check the filesize for non-zero.

Or if you mean just when the file download has completed, listen for the end on the WriteStream.