USB
===

At the time of development, there are no known consumer fingerprint readers
which do not operate over the USB bus. Therefore the library is designed around
the fact that each driver drivers USB devices, and each device is a USB device.
If we were to ever support a non-USB device, some rearchitecting would be
needed, but this would not be a substantial task.


GLib
====

Although the library uses GLib internally, libfprint is designed to provide
a completely neutral interface to it's application users. So, the public
APIs should never return GLib data types or anything like that.


Two-faced-ness
==============

Like any decent library, this one is designed to provide a stable and
documented API to it's users: applications. Clear distinction is made between
data available internally in the library, and data/functions available to
the applications.

This library is confused a little by the fact that there is another 'interface'
at hand: the internal interface provided to drivers. So, we effectively end
up with 2 APIs:

 1. The external-facing API for applications
 2. The internal API for fingerprint drivers