Add ICU (58.2) package

This adds the ICU (International Components for Unicode) package version 58.2 in preparation for building a package for the .NET Core system.

Tested as working properly on Samsung XE50013-K01US.

packages/icu4c.rb

+require 'package'
+
+class Icu4c < Package
+  version '58.2'
+  source_url 'http://download.icu-project.org/files/icu4c/58.2/icu4c-58_2-src.tgz'
+  source_sha1 'b67913c90a484c59fda011797c6f3959d84bdc7c'
+
+  def self.build
+    FileUtils.cd('source') do
+      system "./configure", "--without-samples", "--without-tests"
+      system "make"
+    end
+  end
+  
+  def self.install
+    FileUtils.cd('source') do
+      system "make", "DESTDIR=#{CREW_DEST_DIR}", "install"
+    end
+  end         
+end