Move tests into Codesleeve\Stapler namespace.

Tests have now been moved into the Codesleeve\Stapler namespace so that
there are no naming conflicts with the version of TestCase that's being
used.
Update composer.json to require laravel/framework.

Updated composer.json so that it now requires laravel/framework instead
of relying upon illuminate/foundation.
Fix bug in Resizer when resizing 'auto'.

Fixed a bug in the resize auto method of the Resizer class.
Implement ability to auto-orient images.

Implemented to ability to auto-orient images by setting the auto-orient
flag inside the convert_options for a given style.