Add httrack package

packages/httrack.rb

+require 'package'
+
+class Httrack < Package
+  description 'HTTrack is a free (GPL, libre/free software) and easy-to-use offline browser utility. It allows you to download a World Wide Web site from the Internet to a local directory, building recursively all directories, getting HTML, images, and other files from the server to your computer.'
+  homepage 'http://www.httrack.com/'
+  version '3.49.2'
+  source_url 'http://mirror.httrack.com/httrack-3.49.2.tar.gz'
+  source_sha256 '3477a0e5568e241c63c9899accbfcdb6aadef2812fcce0173688567b4c7d4025'
+
+  def self.build
+    system './configure'
+    system 'make'
+  end
+
+  def self.install
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install"
+  end
+end