Add emoji praises

[hadley]

Like 👍 and 🎉. Need some way of detecting if they're supported in current terminal (if that's even possible)

[gaborcsardi]

Cool. Proper detection is not possible, but we can make good guesses.

[gaborcsardi]

So there is actually this that we can use: https://github.com/richfitz/remoji
I don't think @richfitz wants to submit it to CRAN, but I can. :)

[richfitz]

🤘 I'll see how it fares against current checks and we can sort something out.

[maelle]

@richfitz there's this as well https://github.com/GuangchuangYu/emojifont/ (for graphs but there's a search function)