Add Koala.app

[illusionfield]

Node-webkit based GUI app for Less, Sass, Compass and CoffeeScript compilation.

[vitorgalvao]

Ingenious solution, but unfortunately we cannot have it right now (see Homebrew/homebrew-cask-versions#689 (comment)).

Pinging @rolandwalker for a record of one more cask that would benefit from a change in architecture.

[rolandwalker]

Thanks for pinging me!

Yes, the Cask is very nice, and it's our fault for having the limitation.

I've been thinking about this in relation to #5043 as well. The similarity is the need to defer action. Perhaps all the ordinary stanzas should accept a do block, within which is the code to fill in the value, execution of which is deferred until the value is needed.