make sure "after" blocks really run last

and make it self-documenting by changing class name

lib/cask/artifact.rb

@@ -6,7 +6,7 @@ require 'cask/artifact/hardlinked'
 
 require 'cask/artifact/app'
 require 'cask/artifact/binary'
-require 'cask/artifact/block'
+require 'cask/artifact/after_block'
 require 'cask/artifact/colorpicker'
 require 'cask/artifact/font'
 require 'cask/artifact/nested_container'
@@ -37,10 +37,10 @@ module Cask::Artifact
       Cask::Artifact::Widget,
       Cask::Artifact::Service,
       Cask::Artifact::CaskroomOnly,
-      Cask::Artifact::Block,
       Cask::Artifact::Binary,
       Cask::Artifact::InputMethod,
       Cask::Artifact::ScreenSaver,
+      Cask::Artifact::AfterBlock,
     ]
   end
 

lib/cask/artifact/after_block.rb

@@ -1,4 +1,4 @@
-class Cask::Artifact::Block < Cask::Artifact::Base
+class Cask::Artifact::AfterBlock < Cask::Artifact::Base
   def self.me?(cask)
     cask.artifacts[:after_install].any? ||
       cask.artifacts[:after_uninstall].any?

test/cask/artifact/after_block_test.rb

@@ -1,6 +1,6 @@
 require 'test_helper'
 
-describe Cask::Artifact::Block do
+describe Cask::Artifact::AfterBlock do
   describe 'install' do
     it 'calls the specified block after installing, passing the cask' do
       called      = false
@@ -15,7 +15,7 @@ describe Cask::Artifact::Block do
       end
 
       cask = CaskWithAfterInstall.new
-      Cask::Artifact::Block.new(cask).install
+      Cask::Artifact::AfterBlock.new(cask).install
 
       called.must_equal true
       yielded_arg.must_equal cask
@@ -36,7 +36,7 @@ describe Cask::Artifact::Block do
       end
 
       cask = CaskWithAfterUninstall.new
-      Cask::Artifact::Block.new(cask).uninstall
+      Cask::Artifact::AfterBlock.new(cask).uninstall
 
       called.must_equal true
       yielded_arg.must_equal cask