Cleaned whitespace.
...
Redone building `drupal-mode-map`.

This way it is easier to also add the mnemonic keys / functions to other
key bindings. I.e. I do the following in my .emacs to map them to the
hyper key:

```
(add-hook 'drupal-mode-hook (lambda ()
                              (dolist (elem drupal-mode-map-alist)
                                (local-set-key `[(hyper ,(car elem))] (cdr elem)))))
```
Don't delete `'trailing` form `whitespace-style` after all.

`whitespace-style` not only decides what kind of whitespace gets
highlighted by `whitespace-mode` but also what kind of whitespace gets
removed by `whitespace-cleanup`.