Remove dependency on the money gem

No longer used or needed; the code will continue to work if Money is
passed in since `respond_to?` checks are used to unwrap passed in Money.

Gemfile_common

@@ -8,5 +8,3 @@ group :test, :remote_test do
   gem 'samurai', '>= 0.2.25'
   gem 'braintree', '>= 2.0.0'
 end
-
-gem 'money', '5.0.0', :platforms => [:ruby_18]

activemerchant.gemspec

@@ -21,7 +21,6 @@ Gem::Specification.new do |s|
 
   s.add_dependency('activesupport', '>= 3.2.14', '< 5.0.0')
   s.add_dependency('i18n', '>= 0.6.9')
-  s.add_dependency('money', '< 7.0.0')
   s.add_dependency('builder', '>= 2.1.2', '< 4.0.0')
   s.add_dependency('json', '~> 1.7')
   s.add_dependency('active_utils', '~> 2.2.0')

test/remote/gateways/remote_orbital_test.rb

@@ -81,15 +81,6 @@ def test_failed_capture
     assert_equal 'Bad data error', response.message
   end
 
-  def test_successful_purchase_with_money
-    response = nil
-    silence_warnings do
-      assert response = @gateway.purchase(Money.new(100), @credit_card, @options)
-    end
-    assert_success response
-    assert_equal 'Approved', response.message
-  end
-
   # == Certification Tests
 
   # ==== Section A