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/js_hint.rb

@@ -0,0 +1,13 @@
+class JasmineDev < Thor
+
+  desc "js_hint", "Run Jasmine source through JSHint"
+  def js_hint
+    say JasmineDev.spacer
+
+    return unless node_installed?
+
+    say "Running JSHint on Jasmine source and specs...", :cyan
+
+    run_with_output "node jshint/run.js", :capture => true
+  end
+end