Use rescue_from only on production for errors

Errors:
  ActionController::RoutingError
  ActionController::UnknownController
  ActiveRecord::RecordNotFound
Create static 404 error page
Remove rescue_from from exception handler

Errors:
  ActionController::RoutingError
    ActionController::UnknownController
      ActiveRecord::RecordNotFound
Remove render_404 and custom template 404 from views

The method render_404 is not been used anymore.
Merge pull request #304 from neighborly/jl-remove-rescue

Remove rescue_from from exception handler