Slim 3.0 support

[Rudloff]

Are there plans to make SlimViews compatible with Slim 3.0?

[silentworks]

The core team will only maintain the Twig-View and PHP-View for Slim 3, we don't feel we could justify maintaining the Smarty implementation since none of us use it. You can however fork the Twig-View and create a Smarty-View based off that for Slim 3 and I will link to it.

[mathmarques]

I made a Smarty-View based on Twig-View.
See on: https://github.com/mathmarques/Smarty-View