Add koans for floats, rename to numbers koans, reposition on the list

lib/koans/05_tuples.ex

@@ -1,37 +0,0 @@
-defmodule Tuples do
-  use Koans
-
-  @intro "Tuples"
-
-  koan "Tuples can contain different things" do
-    assert {:a, 1, "hi"} == ___
-  end
-
-  koan "Tuples have a size" do
-    assert tuple_size({:a, :b, :c}) == ___
-  end
-
-  koan "You can pull out individual elements" do
-    assert elem({:a, "hi"}, 1) == ___
-  end
-
-  koan "You can change individual elements of a tuple" do
-    assert put_elem({:a, "hi"}, 1, "bye") == ___
-  end
-
-  koan "You can also simply extend a tuple with new stuff" do
-    assert Tuple.insert_at({:a, "hi"}, 1, :new_thing) == ___
-  end
-
-  koan "Add things at the end" do
-    assert Tuple.append({"Huey", "Dewey"}, "Louie") == ___
-  end
-
-  koan "Or remove them" do
-    assert Tuple.delete_at({:this, :is, :not, :awesome}, 2) == ___
-  end
-
-  koan "Turn it into a list in case you need it" do
-    assert Tuple.to_list({:this, :can, :be, :a, :list}) == ___
-  end
-end