Add sfk package

packages/sfk.rb

+require "package"
+
+class Sfk < Package
+  description 'The Swiss File Knife - A Command Line Tools Collection for Windows / Linux / Mac.'
+  homepage 'http://swissfileknife.sourceforge.net/'
+  version "1.8.6"
+  source_url "https://sourceforge.net/projects/swissfileknife/files/1-swissfileknife/1.8.6/sfk-1.8.6.tar.gz"
+  source_sha1 "d45d80d8a452d121ad85ec1d909fb3f85c17ee3f"
+
+  def self.build
+    system "./configure"
+    system "make"
+  end
+
+  def self.install
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install"
+  end
+end
+