remove/disable some settings/packages

init.el: remove marmalade, it's too outdated and so I pretty much never
use it.
init.el: disable nlinum - it's causing a bug that won't let me open a
new frame.
init.el: enable web-mode
keybindings.el: disable keybindings meant to replace awkward keybindings
resulting from switching Ctrl and Alt key positions. I've swapped back
the keys so it's no longer necessary.
setup-org-agenda.el: disable org-habit.
setup-org-mode.el: hide leading stars