Updated laptop setup instructions with Samba/Kerberos fileshare info.
Dotfile updates:

- Xsession: set Xmodmap; start dropboxd; update redshift location to MTV
- vimrc: add alias for BufExplorer.
- env: misc aliases.
- emacs: font size adjustment for "old" eyes / HiDPI laptop screen.
- doc/setup-fedora.txt: some additional notes about KVM setup.