Add ghostscript package

packages/ghostscript.rb

+require 'package'
+
+class Ghostscript < Package
+  description 'Ghostscript is the name of a set of software that provides an interpreter for the PostScript language and the PDF file format.'
+  homepage 'https://www.gnu.org/software/ghostscript/'
+  version '9.14.1'
+  source_url 'ftp://ftp.gnu.org/gnu/ghostscript/gnu-ghostscript-9.14.1.tar.xz'
+  source_sha1 'd2ac2229ee53b6f8594980da3c6a0819c99ecfa0'
+
+  depends_on 'lcms'
+  depends_on 'libjpeg'
+
+  def self.build
+    system './configure'
+    system 'make'
+  end
+
+  def self.install
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install"
+  end
+end