Set up less awkward key binding for expand-region.
Start using filter groups for Ibuffer.

For now, use separate groups for

- Dired buffers
- temporary buffers (*Messages*, *Compile-Log*, etc.)
- everything else.
Declutter ~: Move .ido.last file to .emacs.d directory.
Declutter ~: Move .recentf file to .emacs.d directory.
Declutter ~: Move .smex-items file to .emacs.d directory.
Remove obsolete code that adds magit-revert-buffer-hook to
git-gutter:update-hooks.

As of
https://github.com/syohex/emacs-git-gutter/commit/e2012c3e98aa670c32c6f4b5501c46d04cdbcd6a,
this is built in.
Ignore .ido.last, .recentf, and .smex-items files.