Re-implemented all development Rake tasks in Thor. Now actually tested.

Fixes:
* https://www.pivotaltracker.com/story/show/25484287 & https://github.com/pivotal/jasmine/issues/183
* https://www.pivotaltracker.com/story/show/25485401 & https://github.com/pivotal/jasmine/issues/189
* https://www.pivotaltracker.com/story/show/25485953 & https://github.com/pivotal/jasmine/issues/159

tasks/jasmine_dev/build_standalone_distribution.rb

@@ -0,0 +1,49 @@
+class JasmineDev < Thor
+  include Thor::Actions
+
+  desc "build_standalone_distribution", "Build Jasmine standalone distribution"
+  def build_standalone_distribution(download_dir = File.expand_path(File.join('.', 'pages', 'downloads')))
+    invoke :build_distribution
+
+    say JasmineDev.spacer
+
+    say "Building standalone distribution...", :cyan
+
+    say "Staging files...", :yellow
+
+    lib_files.each do |f|
+      copy_file f, File.join(standalone_temp_dir, 'lib', "jasmine-#{version_string}", f)
+    end
+
+    ['src', 'spec'].each do |dir|
+      directory File.join('lib', 'jasmine-core', 'example', dir),
+                File.join(standalone_temp_dir, dir)
+    end
+
+    invoke :build_standalone_runner
+
+    say "Zipping distribution...", :yellow
+
+    inside standalone_temp_dir do
+      run_with_output "zip -rq ../jasmine-standalone-#{jasmine_version}.zip ."
+
+      say "Copying Zip file to downloads directory", :yellow
+      run "cp ../jasmine-standalone-#{jasmine_version}.zip #{download_dir}"
+    end
+
+  end
+
+  no_tasks do
+    def standalone_temp_dir
+      @standalone_temp_dir ||= File.join(Dir.tmpdir, 'jasmine_standalone', "jasmine-standalone-#{version_string}")
+    end
+
+    def lib_files
+      %w{ jasmine.js jasmine-html.js jasmine.css MIT.LICENSE }
+    end
+
+    def example_path
+      File.join('lib', "jasmine-#{version_string}")
+    end
+  end
+end