Remove remaining encoding headers

bin/mutant

@@ -1,5 +1,4 @@
 #!/usr/bin/env ruby
-# encoding: utf-8
 
 trap('INT') do |status|
   exit! 128 + status

lib/mutant/integration/rspec.rb

@@ -1,4 +1,3 @@
-# encoding: UTF-8
 require 'rspec/core'
 require 'rspec/core/formatters/base_text_formatter'
 

lib/mutant/meta/example.rb

@@ -1,5 +1,3 @@
-# encoding: UTF-8
-
 module Mutant
   module Meta
     class Example

lib/mutant/mutator/node/resbody.rb

@@ -1,5 +1,3 @@
-# encoding: UTF-8
-
 module Mutant
   class Mutator
     class Node

lib/mutant/mutator/node/send/index.rb

@@ -1,5 +1,3 @@
-# encoding: UTF-8
-
 module Mutant
   class Mutator
     class Node

lib/mutant/warning_filter.rb

@@ -1,5 +1,3 @@
-# encoding: UTF-8
-
 module Mutant
   # Stream filter for warnings
   class WarningFilter

spec/support/mutation_verifier.rb

@@ -1,5 +1,3 @@
-# encoding: UTF-8
-
 class MutationVerifier
   include Adamantium::Flat, Concord.new(:original_node, :expected, :generated)