Give untyped users a user type

I decided to develop the feature I requested. A form will be displayed at login in. After choosing your type the page wont be available anymore so if the access to switch user is disabled the type chosen is permanent.

documentation:

adapted functions:

• menu hook : new item(path 'choosetype') who calls the form via user_types_page(), access is checked by user_type_user_access_choosetype().
• user hook : case login which checks if you are allready a 'typed' user, and if you're not you'll be directed to the form.

new functions:

• user_type_user_access_choosetype() : If you allready have a type access is denied to the form.
• user_types_page() : Sets up the page to display the form.
• user_types_set_type() : the form where you can choose your type.
• user_types_set_type_submit($form_id, $form_values): inserts your uid and user_type_type in the user_types_user table.

There was an implementation of the idea in HEAD allready, so I left the current implementation with one minor modification based on your suggestions: you can only switch if you currently have the default user type (normal user).

Automatically closed -- issue fixed for two weeks with no activity.