Rework Roots_Wrapping class

Apply the wrapper to any template by creating a new instance.
To use this in a theme either create a new function to wrap the object:
````php
<?php 
function roots_file_path() {
  return Roots_Wrapping('path/to/template/file.php');
}
?>
````
Then include the function:
````php
<?php include roots_file_path; ?>
````
Or just include the new object directly;
````php
<?php include new Roots_Wrapping('path/to/template/file.php'); ?>
````

Or create a new variable for the object include that;
````php
<?php 
$file_wrapper = new Roots_Wrapping('path/to/template/file.php');
include $file_wrapper; 
?>
````