Add putty package

packages/putty.rb

+require 'package'
+
+class Putty < Package
+  description 'Free Telnet, SSH, and Rlogin clients plus a terminal emulator'
+  homepage 'https://www.chiark.greenend.org.uk/~sgtatham/putty/'
+  version '0.70'
+  source_url 'https://the.earth.li/~sgtatham/putty/latest/putty-0.70.tar.gz'
+  source_sha256 'bb8aa49d6e96c5a8e18a057f3150a1695ed99a24eef699e783651d1f24e7b0be'
+
+  def self.build
+    system './configure --without-gtk'
+    system 'make'
+  end
+
+  def self.install
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install"
+  end
+end