Fix a few mistakes.

* postLink() doesn't accept null anymore
* variable names were incorrect.
* missing HTML escaping
Fix missing options parameter for belongsto associations.

In 3.0 you need to provide the options parameter to get select boxes.
FormHelper no longer goes fishing through view variables.
Accessible entity fields should be accessible.
Fix generated actions.

We need belongsTo on the list page, and all associations with the view
page. Edit and Add need the BelongsTo/BelongsToMany associations.
BelongsToMany elements should be the property name not the association name.
Add association properties to accessible fields.

The various association fields need to be accessible. If they are not
the data cannot be marshalled into an entity.