Add formula for PhpDocumentor 2
user
```ruby
require 'formula'
require File.expand_path("../../Requirements/php-meta-requirement", Pathname.new(__FILE__).realpath)
require File.expand_path("../../Requirements/phar-requirement", Pathname.new(__FILE__).realpath)

class Phpdocumentor < Formula
  homepage 'http://www.phpdoc.org'
  url 'http://www.phpdoc.org/phpDocumentor.phar'
  sha1 'ca66cc4e95aaefff7bc4341bd9d2d1d25c47eea3'
  version '2.0.0a12'

  depends_on PhpMetaRequirement
  depends_on PharRequirement

  def install
    libexec.install "phpDocumentor.phar"
    sh = libexec + "phpdoc"
    sh.write("#!/usr/bin/env bash\n\n/usr/bin/env php -d allow_url_fopen=On -d detect_unicode=Off #{libexec}/phpDocumentor.phar $*")
    chmod 0755, sh
    bin.install_symlink sh
  end

  def caveats; <<-EOS.undent
    Verify your installation by running:
      "phpdoc --version".

    You can read more about phpdocumentor by running:
      "brew home phpdocumentor".
    EOS
  end

end
```
assistant