Add libunistring (0.9.7) package

libunistring provides functions for manipulating Unicode strings and
for manipulating C strings according to the Unicode standard.

Tested as working properly on Samsung XE50013-K01US.

packages/libunistring.rb

+require 'package'
+
+class Libunistring < Package
+  version '0.9.7'
+  source_url 'http://ftp.gnu.org/gnu/libunistring/libunistring-0.9.7.tar.xz'
+  source_sha1 '7d92687a50fea7702e8052486dfa25ffc361c9f3'
+
+  depends_on "glibc"
+
+  def self.build
+    system "./configure --prefix=/usr/local"
+    system "make"
+  end
+
+  def self.install
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install" 
+  end
+end