Remove code made obsolete by Bundler dependency

Since 2cdf739baa started always loading
bundler/setup during tests, we can get rid of some manual load path
setup and dependency checking. We should also explicitly add bundler as
a development dependency.

Rakefile

@@ -7,17 +7,6 @@ require 'pry/version'
 CLOBBER.include('**/*~', '**/*#*', '**/*.log')
 CLEAN.include('**/*#*', '**/*#*.*', '**/*_flymake*.*', '**/*_flymake', '**/*.rbc', '**/.#*.*')
 
-def check_dependencies
-  require 'bundler'
-  Bundler.definition.missing_specs
-
-  eval('nil', TOPLEVEL_BINDING, '<main>') # workaround for issue #395
-rescue LoadError
-  # if Bundler isn't installed, we'll just assume your setup is ok.
-rescue Bundler::GemNotFound
-  raise RuntimeError, "You're missing one or more required gems. Run `bundle install` first."
-end
-
 desc "Set up and run tests"
 task :default => [:test]
 
@@ -28,7 +17,6 @@ end
 
 desc "Run tests"
 task :test do
-  check_dependencies unless ENV['SKIP_DEP_CHECK']
   paths =
     if explicit_list = ENV['run']
       explicit_list.split(',')
@@ -47,7 +35,6 @@ end
 
 desc "Run pry (you can pass arguments using _ in place of -)"
 task :pry do
-  check_dependencies unless ENV['SKIP_DEP_CHECK']
   ARGV.shift if ARGV.first == "pry"
   ARGV.map! do |arg|
     arg.sub(/^_*/) { |m| "-" * m.size }

pry.gemspec

@@ -20,6 +20,7 @@ Gem::Specification.new do |s|
   s.add_dependency 'slop',          '~> 3.4'
   s.add_dependency 'method_source', '~> 0.8'
 
+  s.add_development_dependency 'bundler', '~> 1.0'
   s.add_development_dependency 'bacon', '~> 1.2'
   s.add_development_dependency 'rake',  '~> 10.0'
   s.add_development_dependency 'mocha', '~> 1.0'

spec/helper.rb

@@ -1,7 +1,10 @@
-require "bundler/setup"
+require 'bundler/setup'
 require 'mocha/api'
-require "ostruct"
+require 'ostruct'
+
+require 'pry'
 require 'pry/test/helper'
+
 require_relative 'spec_helpers/bacon'
 require_relative 'spec_helpers/mock_pry'
 require_relative 'spec_helpers/repl_tester'
@@ -11,11 +14,6 @@ if ENV["COVERAGE"]
   SimpleCov.start
 end
 
-unless Object.const_defined? 'Pry'
-  $:.unshift File.expand_path '../../lib', __FILE__
-  require 'pry'
-end
-
 class Module
   public :remove_const
   public :remove_method