Enable passing of Traversable Objects to '@each'-structures

My suggestion to fix #25, allowing the use of Eloquent Collections when rendering nested Views with @each Structures.

>The renderEach method (View/Environment.php:120) uses an 'array' type-hint for $data, causing type-mismatch issues when passing Eloquent Collections (despite being iterable like an array).

EDIT: Unfortunately, Travis failed to Clone Mockery in the second build job..