Get some tests working (partially closes #112)

See #112.

Repaired tests:

 * test/rails/caching_test.rb
 * test/rails/controller_methods_test.rb
 * test/tree_node_test.rb
 * test/widget_test.rb

Tests still are omit:

 * test/rails/widget_generator_test.rb
 * test/rails/view_helper_test.rb
 * test/rails/rails_integration_test.rb