Add lists method to Collection class

Signed-off-by: Dries Vints <dries.vints@gmail.com>
Remove duplicate lists function from Eloquent Collection

Signed-off-by: Dries Vints <dries.vints@gmail.com>
Fix incorrect variable name in docblock

Signed-off-by: Dries Vints <dries.vints@gmail.com>
Add a space between 2 lines

Signed-off-by: Dries Vints <dries.vints@gmail.com>
Merge pull request #1535 from driesvints/feature/lists-function-on-collection-class

Add lists method to Collection class
Allow for host on Iron.io configuration. Closes #1525.
Merge branch '4.0'