Improved car and passenger controllers.

- Logic is now more consistent
- Naming conventions, single quotes, etc. are same.
- Factorized logging of acceptable formats into app's controller.
Improved carpooling controllers and views.

- Translated car form and shared car table and form.
- Simplified DOM elements' IDs.
- Factorized logic between car and passenger controllers.
- Various code clean-ups.
- Double quotes changed to single quotes where possible.
HTML-only working properly for cars and passengers. Controllers improved.