Adds some dubug print statements.
Adds unit tests and does some refactoring.

Adds unit tests to PendulumViewController.

Refactors the use of the BaseController animator method by eliminating
the animator attar in various VCs.

Adds a *.tmp to gitignore file.

Adds instructional labels to some VCs that were missing labels as used
by the origin Objective-C catalog.

Adds Gravity Spring VC.

Adds @help_methods.do_methods_respond test helper to
spec/controllers/attachments_view_controller_spec.rb.

Removes @subject in favour of  tests CollisionViewController .