Is there any one who can recommend an Atom package for haxe that would enable goto declaration of a property of a method in a class?
On Atom you can use for Haxe Toolkit the Haxe package, and the language-haxe package also, if you want to develop on Haxe for games you can use the Heaps Toolkit also, who is also developed from the same guys as Haxe. You can search for videos about this, they are several, also you can use Haxe with OpenFL so you can develop with Flash, but believe me, its not Flash.
One more thing in Atom, it is enough just to create a javascript project, from there you are safe.