Remove binary_test because it's not actually needed

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

lib/util.ex

@@ -14,26 +14,4 @@ defmodule Omnibot.Util do
   def denotify_nick(nick) do
     String.graphemes(nick) |> Enum.join("\u200b")
   end
-
-  def binary_search([], _key) do
-    nil
-  end
-
-  def binary_search([{key, value} | _], key) do
-    {0, value}
-  end
-
-  @doc "Attempts to find to find the given key in a sorted associative array."
-  def binary_search(list, key) do
-    {head, tail} = Enum.split(list, trunc(length(list) / 2))
-    [{mid, _} | _] = tail
-    if key < mid do
-      binary_search(head, key)
-    else
-      case binary_search(tail, key) do
-        nil -> nil
-        {index, item} -> {index + length(head), item}
-      end
-    end
-  end
 end