Update to idiomatic ember 1.0

 * Only auto-save todo when isCompleted changes, not when title changes
 * use .on('didInsertElement') in view
 * Register handlebars helper for edit-todo view
 * Put controller actions in `actions` hash
 * bindAttr -> bind-attr, linkTo -> link-to
 * use handlebars `input` helper
 * use quotes around strings only in handlebars templates, not around
 property paths
 * Remove 'text-cleared' sent action from EditTodoView,
   move auto-removal functionality into TodoController.
   Use debounce to prevent multiple calls to `removeTodo`
 * Save the todo in the `createTodo` action of TodosController
 * Trim an edited todo's title before checking to remove it.
 * Per the TodoMVC spec, cancel changes to a todo's title when escape is pressed
 (use a `bufferedTitle` property when editing a todo)
 * remove unused buttonClass:hidden
 * Put jshint globals declarations all on one line (valid jshint format,
 requested by todomvc)