Custom Field Type Hooks

I have added the ability to create custom callback functions to create custom field outputs to the options panel.

To add a call back you add the following code after including the frameworks options.php file:

```upfw_add_custom_field('custom_field_name', 'custom_field_function');```

You then create a function for that custom_field_name like so:

```php
function custom_field_function($value, $attr, $name)
{
    // add custom output for field type that matches assigned field_name
}
```

I decided to add the $name attribute so that the user did not have to create the name value like the built in functions do.

There is also a fatal error fix and white space fixes.

I have tested this on WP 3.5 and 3.5.1