Remove shen.

The Shen 3.1 source tarball has frequent in-place changes, which causes
the formula checksum to break.

Would accept this as a head-only formula in Homebrew-ALT, or if upstream
stops doing these sorts of non-versioned updates.

Formula/shen.rb

@@ -1,32 +0,0 @@
-require 'formula'
-
-class Shen < Formula
-  homepage 'http://www.shenlanguage.org/'
-  url 'http://www.shenlanguage.org/download/Shen3.1.zip'
-  md5 'ecc1ed39c499417b9408157982559319'
-
-  if ARGV.include? "--sbcl"
-    depends_on 'sbcl'
-  else
-    depends_on 'clisp'
-  end
-
-  def options
-    [["--sbcl", "Build SBCL version."]]
-  end
-
-  def install
-    if ARGV.include?("--sbcl") then
-      system "cp K\\ Lambda/* Platforms/SBCL"
-      safe_system "cd Platforms/SBCL; sbcl --load install.lsp"
-      system "mv Platforms/SBCL/Shen.exe shen"
-    else
-      system "cp K\\ Lambda/* Platforms/CLisp"
-      safe_system "cd Platforms/CLisp; clisp -i install.lsp"
-      system "echo \"#!/bin/bash\nclisp -M #{prefix}/Shen.mem $*\" > shen"
-      prefix.install ['Platforms/CLisp/Shen.mem']
-    end
-    system "chmod 755 shen"
-    bin.install 'shen'
-  end
-end