Fix using macro for entry module

lib/dsl.ex

@@ -3,9 +3,8 @@ defmodule Dsl do
   Documentation for Dsl.
   """
 
-  def __using__(_) do
+  defmacro __using__(_) do
     quote do
-      import Kernel, except: [div: 2]
       import Dsl.Html
     end
   end

test/dsl/html_test.exs

@@ -1,6 +1,6 @@
 defmodule Dsl.HtmlTest do
   use ExUnit.Case, async: true
-  import Dsl.Html
+  use Dsl
 
   describe "non-void elements" do
     test "renders two divs" do