Move require of optparse to central location

lib/mutant.rb

@@ -9,6 +9,7 @@ require 'equalizer'
 require 'ice_nine'
 require 'morpher'
 require 'open3'
+require 'optparse'
 require 'parallel'
 require 'parser'
 require 'parser/current'

lib/mutant/cli.rb

@@ -1,5 +1,3 @@
-require 'optparse'
-
 module Mutant
 
   # Commandline parser