Highlight the data structure aspect of this repo

[rudderbucky]

It doesn't seem like either etagere or guillotiere actually handle the problem of converting multiple files into one texture (please let me know if I'm wrong here).

If so, wouldn't it be more accurate to highlight that this is a data structure meant to aid the process of atlas creation, and that it doesn't handle the details of creating that texture?

~~I suppose my confusion is on what the actual use case of the allocator would look like. The example in the readme describes how to allocate spaces, but not really how to convert them into usable coordinates of a bigger computed texture~~

Proposed solution: Change the opening of the readme to "A dynamic texture atlas allocator data structure using the shelf packing algorithm."