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

spec/tasks/build_distribution_spec.rb

@@ -0,0 +1,33 @@
+require 'spec_helper.rb'
+
+describe "Build Jasmine task" do
+
+  let(:jasmine_core_dir) { "#{Dir.tmpdir}/jasmine-core" }
+  let(:jasmine_dev) { JasmineDev.new }
+
+  before do
+    reset_dir jasmine_core_dir
+    @output = capture_output { jasmine_dev.build_distribution jasmine_core_dir }
+  end
+
+  it "should say that JSHint is running" do
+    @output.should match(/Running JSHint/)
+    @output.should match(/Jasmine JSHint PASSED/)
+  end
+
+  it "should tell the developer it is building the distribution" do
+    @output.should match(/Building Jasmine distribution/)
+  end
+
+  it "should build jasmine.js in the destination directory" do
+    File.exist?("#{jasmine_core_dir}/jasmine.js").should be_true
+  end
+
+  it "should build jasmine-html.js in the destination directory" do
+    File.exist?("#{jasmine_core_dir}/jasmine-html.js").should be_true
+  end
+
+  it "should build jasmine.css" do
+    File.exist?("#{jasmine_core_dir}/jasmine.css").should be_true
+  end
+end