Remove rr dependency

It was causing spurious failures that I didn't feel like tracking down.

pry-rails.gemspec

@@ -22,5 +22,4 @@ Gem::Specification.new do |s|
   s.add_dependency "pry", ">= 0.9.10"
   s.add_development_dependency "appraisal"
   s.add_development_dependency "minitest"
-  s.add_development_dependency "rr"
 end

spec/railtie_spec.rb

@@ -5,9 +5,27 @@ require 'rails/commands/console'
 
 describe PryRails::Railtie do
   it 'should start Pry instead of IRB and make the helpers available' do
-    mock(Pry).start
-    Rails::Console.start(Rails.application)
-    assert RR.verify
+    # Yes, I know this is horrible.
+    begin
+      $called_start = false
+      real_pry = Pry
+
+      silence_warnings do
+        ::Pry = Class.new do
+          def self.start(*)
+            $called_start = true
+          end
+        end
+      end
+
+      Rails::Console.start(Rails.application)
+
+      assert $called_start
+    ensure
+      silence_warnings do
+        ::Pry = real_pry
+      end
+    end
 
     %w(app helper reload!).each do |helper|
       TOPLEVEL_BINDING.eval("respond_to?(:#{helper}, true)").must_equal true

spec/spec_helper.rb

@@ -1,11 +1,4 @@
 require 'minitest/autorun'
-
-require 'rr'
-
-class MiniTest::Spec
-  include RR::Adapters::RRMethods
-end
-
 require 'config/environment'
 
 # Pry testing stuff (taken from Pry itself)