Add support for cursor based pagination (again)

[rjacobso]

This is an attempt to implement the same logic from #125 but without breaking backwards-compat.

[hippoduck]

What is the correct way to use this to get all products? I used your example code on your other PR, but I get the following error:

No action named lastResourceContainsNextPageInfo is defined for Product in ....

[rjacobso]

You are correct, it seems there was another competing pull request to do this in a different manner. It looks like @tareqtms approved both, but some / most of my changes were removed as part of the merge. - Actually this could have been me screwing it up trying to bring my repo up to date. Looking now ...

[tareqtms]

The working code should be here:

$productResource =  $shopify->Product();
$products = $productResource->get(['limit'=>50]);
$nextPageProducts = $productResource->get($productResource->getNextPageParams());
/* in short: you need to reuse the resource to get the params before making another resource */**

Please follow the thread #101 for more info.