Update to rails 3.1.0

* Bump rails version to 3.1.0 in Gemfile
* Update config files
* Fix bcrypt monkey patch for specs
* Fix TracksController
* Replace track streaming with track download
* Remove assets from application layout

config/initializers/wrap_parameters.rb

@@ -0,0 +1,14 @@
+# Be sure to restart your server when you modify this file.
+#
+# This file contains settings for ActionController::ParamsWrapper which
+# is enabled by default.
+
+# Enable parameter wrapping for JSON. You can disable this by setting :format to an empty array.
+ActiveSupport.on_load(:action_controller) do
+  wrap_parameters :format => [:json]
+end
+
+# Disable root element in JSON by default.
+ActiveSupport.on_load(:active_record) do
+  self.include_root_in_json = false
+end