Parsing arrays with simple element types

Currently, parsing an array with simple types attempts to parse each element of the array.  This produces unintended results for simple types (number, string) etc.

Example:
```javascript

var easyxml = require('easyxml');

var test = {
    data: ['test1', 'test2']
};

console.log('test: ');
console.log(test);

console.log('easyxml.render(test)');
console.log(easyxml.render(test));
```

will produce the following output
```
test: 
{ data: [ 'test1', 'test2' ] }
easyxml.render(test)
<response>
    <data>
        <data>
            <0>t</0>
            <1>e</1>
            <2>s</2>
            <3>t</3>
            <4>1</4>
        </data>
        <data>
            <0>t</0>
            <1>e</1>
            <2>s</2>
            <3>t</3>
            <4>2</4>
        </data>
    </data>
</response>
```

And the intended result is
```
<response>
    <data>
        <data>test1</data>
        <data>test2</data>
    </data>
</response>
```