[PATCH 1-3/3] Emacsy, mru-next and next-buffer have opp semantics

[Amar Singh]

A. Patch: swap prev-buffer <--> next-buffer
Steps to reproduce issue:

;; 1. load emacsy buffers without the fix.
(load "buffer.scm")

;; 2. imagine these are tabs opened in order
(map add-buffer! '(peace satan hell))

;; 3. manually verify that we have these buffers
(buffer-list) ;; (hell satan peace)

;; 4. current buffer should be 'hell
(current-buffer) ;; -> hell
(prev-buffer) ;; -> peace
(next-buffer) ;; -> satan

prev-buffer has next-buffer semantics and vice versa, due to what
mru-next! considers next.

B. Patch: add procedures buffer-next! buffer-prev!

Also, the procedures buffer-next! and buffer-previous! have been added
so that these can be used from a repl without the emacsy gui running.

C. Patch: use #:export form instead of define*-public forms
Have the API in one place at the top of the file

0001-cleanup-buffer.scm-export-using-export-keyword.patch
Description: Text Data

0002-buffers.scm-add-procedures-buffer-previous-buffer-ne.patch
Description: Text Data

0003-swap-next-buffer-prev-buffer-semantics.patch
Description: Text Data