Helper functions for radio, checkbox and select boxes

Helper functions for radio, checkbox and select boxes in the formbuilder class to simplify the creation of these field types without having to memorise the expanded and multiple options for each one.

**Checkboxes**

```
'expanded' => true, 'multiple' => true,
```

**Radio**

```
'expanded' => true, 'multiple' => false,
```

**Select**

```
'expanded' => false, 'multiple' => false,
```

