Use real-world samples for JRuby and Rubinius executables

https://github.com/shoes/shoes4/blob/master/shoes-swt/bin/shoes-swt
https://github.com/txus/rexpl/blob/master/bin/rexpl

samples/Ruby/jruby

@@ -1,3 +0,0 @@
-#!/usr/bin/env jruby
-
-puts "This is a JRuby executable example."

samples/Ruby/rexpl

@@ -0,0 +1,4 @@
+#!/usr/bin/env rbx
+$: << 'lib'
+require 'rexpl'
+Rexpl::Environment.run

samples/Ruby/shoes-swt

@@ -0,0 +1,11 @@
+#!/usr/bin/env jruby
+lib_directory = File.expand_path('../../lib', __FILE__)
+$LOAD_PATH << lib_directory
+
+if File.exist?("Gemfile")
+  require "bundler/setup"
+  Bundler.require
+end
+
+require 'shoes/ui/cli'
+Shoes::CLI.new("swt").run ARGV