Include an editor

[embray]

The %edit magic doesn't work, since if $EDITOR is not set it defaults to vi, but vi/vim are not installed either so just nothing happens. We could either include vim in the distribution, or preconfigure $EDITOR to something windows-ish (either notepad or wordpad--probably the latter since it handles unix newlines correctly, though the former is more familiar, and is also getting unix newline support soon).

Or we could include a text-based editor, but something more novice-friendly (say, nano).

[embray]

Huh, actually it looks like vi is included, in which case I'm not sure why %edit isn't working.

[embray]

Nevermind, it does work; I was just using it wrong. Nevertheless, perhaps we should include a friendlier default than vi (it actually is vim, but running in vi-mode, and plain vim curiously is not included).

[slel]

Maybe ATOM, customized to use Python syntax highlighting
for all Python, Cython and Sage files (.py, .pyx, .spyx, .sage)?

[embray]

No, nothing GUI-based. The idea of this issue was to just have a reasonable default, not a full-featured editor included.