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/release.rb

@@ -0,0 +1,16 @@
+class JasmineDev < Thor
+
+  desc 'release_prep', "Update version and build distributions"
+  def release_prep
+    say JasmineDev.spacer
+
+    say "Building Release...", :cyan
+
+    return unless pages_submodule_installed?
+
+    invoke :write_version_files
+    invoke :build_distribution
+    invoke :build_standalone_distribution
+    invoke :build_github_pages
+  end
+end