Trying to clean up document handlers.

src/atom/document.coffee

@@ -19,6 +19,12 @@ class Document extends Pane
   @register: (test) ->
     Document.handlers[@name] = {test, handler: this}
 
+  @forURL: ->
+    if handler = @handler window.url
+      new handler
+    else
+      throw "I DON'T KNOW ABOUT #{window.url}"
+
   constructor: ->
 
   open: (path) ->

src/startup.coffee

@@ -33,10 +33,7 @@ atom.app = new App
 for name, method of atom.app
   atom[name] = atom.app[name]
 
-if handler = Document.handler window.url
-  atom.document = new handler
-  atom.document.open window.url
-else
-  throw "I DON'T KNOW ABOUT #{window.url}"
+atom.document = Document.forURL window.url
+atom.document.open window.url
 
 window.startup()