feat: using coffee file for space-pen-dsl

Author: aminya

src/atom-utils.js

@@ -37,4 +37,4 @@ export Ancestors from './mixins/ancestors'
 export AncestorsMethods from './mixins/ancestors'
 export DisposableEvents from './mixins/disposable-events'
 export EventsDelegation from './mixins/events-delegation'
-export SpacePenDSL from './mixins/space-pen-dsl'
+export SpacePenDSL from './mixins/space-pen-dsl.coffee'

src/mixins/space-pen-dsl.coffee

@@ -23,8 +23,7 @@ class BabelSpacePenDSL extends Mixin
   buildContent: ->
     SpacePenDSL.buildContent(this, @constructor.content) if @constructor.content?
 
-module.exports =
-class SpacePenDSL extends Mixin
+export default class SpacePenDSL extends Mixin
   @Babel: BabelSpacePenDSL
 
   @includeInto: (klass) ->