Allow mixing short syntax with a more verbose syntax.

Verbose syntax would be an array of with "name" and "value" attributes, such as:
```
[
    'name' => 'foo',
    'value' => 'bar',
]
```

Since there are no attributes this could be written using a short syntax, such as:
```
[
    'foo' => 'bar',
]
```

With this change we now are able to mix those syntax, eg:
```
[
    'short' => 'syntax',
    [
        'name' => 'verbose',
        'value' => 'syntax',
    ],
]
```

The "verbose" syntax is supposed to be used when having multiple elements with same name or when a element has attributes.
Merge pull request #8 from renan/short-syntax

Allow mixing short syntax with a more verbose syntax.