Style guide

This outlines recommended practices for contributors to this package.

Naming

• Type parameters: use F for F <: Fixed, N for N <: Normed, and X for X <: FixedPoint. Use f for the number of fractional bits.
• Use Ti for Ti <: Integer, Tf for Tf <: AbstractFloat, and Tw for widened types.
• T should refer to the underlying "raw" type.