emacs: Add package-filter, pin some packages.

I want MELPA for some packages, but certainly not for everything.
emacs: Add some `s'-mode mappings.
emacs: Add evil-leader initialization.
emacs: Add evil-surround initialization/mappings.
emacs: Add ido-mode initialization.
emacs: Add magit status/blame bindings.
emacs: Add undo-tree undo/redo and visualizer mappings.
emacs: Add elisp hooks for keywords and paredit.
emacs: Add visual binding to jump within selection.
zsh: Fix indentation in zlogin.