Added support for multiple replace tags

This "fixes" the issue #13.

Since the Array format is already supported, I thought that I'd modify a little bit the structure you proposed to be like so:

```js
rjs: {
  src: ['data-main.js', 'require-src.js'],
  tpl: '<script src="%s"></script>'
}
```

Would output

```html
<script src="data-main.js"></script>
<script src="require-src.js"></script>
```

Using an Array in an Array:

```js
rjs: {
  src: [['data-main.js', 'require-src.js']],
  tpl: '<script data-main="%s" src="%s"></script>'
}
```

Would output

```html
<script data-main="data-main.js" src="require-src.js"></script>
```

And support for multiple script output, with multiple replacement:

```js
rjs: {
  src: [['data-main.js', 'require-src.js'], ['data-main2.js', 'require-src2.js']],
  tpl: '<script data-main="%s" src="%s"></script>'
}
```

Would output

```html
<script data-main="data-main.js" src="require-src.js"></script>
<script data-main="data-main2.js" src="require-src2.js"></script>
```

What do you think about such a solution ?