Use each instead of $.each

Iterating through the jQuery elements with `each` is more similar to
other iterators we use. Furthermore, we avoid declaring the `index`
variable we don't use.

app/assets/javascripts/documentable.js.coffee

@@ -3,8 +3,8 @@ App.Documentable =
   initialize: ->
 
     inputFiles = $(".js-document-attachment")
-    $.each inputFiles, (index, input) ->
-      App.Documentable.initializeDirectUploadInput(input)
+    inputFiles.each ->
+      App.Documentable.initializeDirectUploadInput(this)
 
     $("#nested-documents").on "cocoon:after-remove", ->
       App.Documentable.unlockUploads()

app/assets/javascripts/imageable.js.coffee

@@ -2,8 +2,8 @@ App.Imageable =
 
   initialize: ->
     inputFiles = $(".js-image-attachment")
-    $.each inputFiles, (index, input) ->
-      App.Imageable.initializeDirectUploadInput(input)
+    inputFiles.each ->
+      App.Imageable.initializeDirectUploadInput(this)
 
     $("#nested-image").on "cocoon:after-remove", ->
       $("#new_image_link").removeClass("hide")

app/assets/javascripts/map.js.coffee

@@ -3,9 +3,8 @@ App.Map =
   initialize: ->
     maps = $("*[data-map]")
 
-    if maps.length > 0
-      $.each maps, (index, map) ->
-        App.Map.initializeMap map
+    maps.each ->
+      App.Map.initializeMap(this)
 
     $(".js-toggle-map").on
       click: ->