Embedded graphics transformations

This crate provides generic implementations of simple transformations - rotate by 90 degree increments, mirroring and transposing.

These are intended to adapt generic graphics code to a particular display dimensions and orientation. It provides fixed transformation types which have no space overhead and minimal time overhead to adjust coordinates and dimensions. It also provides runtime-configurable rotations with minimal additional space and time overheads.

Because this is generic, it cannot take advantage of any hardware support for image rotation. In particular, DrawTarget::fill_contiguous will not use any specialized implementation.

This crate is no-std and has minimal additional dependencies.