Give control over which variation selectors to print

[arp242]

The U+FE0F and U+FE0E can control if a character is displayed in "character style" or "emoji style"; this matters for some characters that have representations in both:

↔︎ (fe0e, text)
↔️ (fe0f, emoji)

These things are kind "hidden" and tricky, because many editors don't display them at all, including Vim, and different environments have different defaults. I lost quite a bit of time tracking down a problem with this a few weeks ago :-/

Either way, there should be a flag for the emoji command to say which variation selector to use. This also applies to the other commands, but those all assume there is just one codepoint now in various columns, so meh.