#27 Better buffer handling

Due to how the buffers are handled from `atto`, you can only go one direction. It would be nice for the buffers to be more like how GNU Emacs does it where the next buffer to switch to is the previous one you were on. This would likely be a very easy thing to add just by storing the previous buffer in a temp buffer or something. However, I may consider doing this another way to make the code make more sense.