Rip the transport code completely out of puffs and generalize it
into an independent module which will be used for multiple purposes
in the future. This module is called the Pass-to-Userspace
Transporter (known as "putter" among friends).
This is very much work-in-progress and one dependency with puffs
remains: the request framing format.
The device name is still /dev/puffs, but that will change soon.
Users of puffs need the following in their kernel configs now:
pseudo-device putter