Add Teacup Entrant

[Teacup](https://github.com/goodeggs/teacup) is the latest in a whole family of markup-as-java/coffeescript templating languages that aren't represented in template-chooser.  Check out 

- [CoffeeKup](https://github.com/mauricemach/coffeekup)
- [CoffeeCup](https://github.com/gradus/coffeecup)
- [DryKup](https://github.com/mark-hahn/drykup)

for some backstory.