Move specialized formulae base classes into a new file

Library/Homebrew/formula.rb

@@ -2,6 +2,7 @@ require 'download_strategy'
 require 'formula_support'
 require 'hardware'
 require 'extend/fileutils'
+require 'formula_specialties'
 
 
 # Derive and define at least @url, see Library/Formula for examples
@@ -764,18 +765,3 @@ private
     end
   end
 end
-
-# See youtube-dl.rb for an example
-class ScriptFileFormula < Formula
-  def install
-    bin.install Dir['*']
-  end
-end
-
-# See flac.rb for an example
-class GithubGistFormula < ScriptFileFormula
-  def initialize name='__UNKNOWN__', path=nil
-    super name, path
-    @version=File.basename(File.dirname(url))[0,6]
-  end
-end

Library/Homebrew/formula_specialties.rb

@@ -0,0 +1,16 @@
+# Base classes for specialized types of formulae.
+
+# See youtube-dl.rb for an example
+class ScriptFileFormula < Formula
+  def install
+    bin.install Dir['*']
+  end
+end
+
+# See flac.rb for an example
+class GithubGistFormula < ScriptFileFormula
+  def initialize name='__UNKNOWN__', path=nil
+    super name, path
+    @version=File.basename(File.dirname(url))[0,6]
+  end
+end