More sugar for including lists of files in templates

Most of the time you want to include a list of js/css/component files in the same app. This PR allows you to pass a a file or array of files to those functions:

```php
<?php

// include one file
script('news', 'vendor/traceur-runtime/traceur-runtime.min');
script('news', 'vendor/angular/angular.min');
script('news', 'vendor/angular-route/angular-route.min');
script('news', 'vendor/angular-sanitize/angular-sanitize.min');
script('news', 'vendor/angular-animate/angular-animate.min');
script('news', 'vendor/momentjs/min/moment-with-locales.min');
script('news', 'build/app.min');

// include multiple files of the same app
script('news', [
	'vendor/traceur-runtime/traceur-runtime.min',
	'vendor/angular/angular.min',
	'vendor/angular-route/angular-route.min',
	'vendor/angular-sanitize/angular-sanitize.min',
	'vendor/angular-animate/angular-animate.min',
	'vendor/momentjs/min/moment-with-locales.min',
	'build/app.min',
]);
```

@georgehrke @raghunayyar @jancborchardt @icewind1991 @MorrisJobke @th3fallen @jbtbnl @LEDfan