Extra example EXR-2.0 images on github

I have just uploaded a series of example multipart images to the 
openexr-images github repository
https://github.com/openexr/openexr-images/tree/master/Beachball

These consist of a single part, backwards compatible, file sequence, and 
the same data stored in multiple part files with ten parts in each file.

A README file explains how the standard layer naming conventions for 
EXR-2.0 have been applied, and highlights some of the peculiarities.

Note these are in some senses an "extreme" multipart files which not all 
existing tools will read correctly.

Peter