Potential data overwrite when reading in chucks #19

Thank you for this great library. I’ve been using it and customizing it for my CDC Host application.

I noticed an issue in the read() API here:

When reading data in multiple chunks from the ring buffer, memcpy always copies into dest without advancing the destination pointer. This overwrites previously read data.

I will push a PR for this. Please help me review. @bertmelis

Thank you.