Add gwt package

Allow gwt command arguments in the scripts

Add postinstall section

packages/gwt.rb

+require 'package'
+
+class Gwt < Package
+  description 'Google Web Toolkit'
+  homepage 'http://www.gwtproject.org/'
+  version '2.8.2'
+  source_url 'https://storage.googleapis.com/gwt-releases/gwt-2.8.2.zip'
+  source_sha256 '970701dacc55170088f5eb327137cb4a7581ebb4734188dfcc2fad9941745d1b'
+
+  binary_url ({
+  })
+  binary_sha256 ({
+  })
+
+  depends_on 'ant'
+  depends_on 'unzip' => :build
+
+  def self.install
+    system "rm -f *.cmd"
+    system "mkdir -p #{CREW_DEST_PREFIX}/bin"
+    system "mkdir -p #{CREW_DEST_PREFIX}/share/gwt"
+    system "cp -r . #{CREW_DEST_PREFIX}/share/gwt"
+    Dir.chdir "#{CREW_DEST_PREFIX}/bin" do
+      system "echo '#!/bin/bash' > i18nCreator"
+      system "echo 'cd #{CREW_PREFIX}/share/gwt' >> i18nCreator"
+      system "echo './i18nCreator \"$@\"' >> i18nCreator"
+      system "chmod +x i18nCreator"
+      system "echo '#!/bin/bash' > webAppCreator"
+      system "echo 'cd #{CREW_PREFIX}/share/gwt' >> webAppCreator"
+      system "echo './webAppCreator \"$@\"' >> webAppCreator"
+      system "chmod +x webAppCreator"
+    end
+  end
+
+  def self.postinstall
+    puts
+    puts "To uninstall completely including projects, execute the following:".lightblue
+    puts "crew remove gwt".lightblue
+    puts "rm -rf #{CREW_PREFIX}/share/gwt".lightblue
+    puts
+  end
+end