Create ScrollView super class

Binds support for page up, page down, move to top,
and move to bottom in the initialize method.

src/app/scroll-view.coffee

@@ -0,0 +1,8 @@
+{View} = require 'space-pen'
+module.exports =
+class ScrollView extends View
+  initialize: ->
+    @on 'core:page-up', => @pageUp()
+    @on 'core:page-down', => @pageDown()
+    @on 'core:move-to-top', => @scrollToTop()
+    @on 'core:move-to-bottom', => @scrollToBottom()