Support Paginating Struct Pointer Slices

[willjleong]

• Added code to check paginated slice item if pointer.
• Use Indirect() if slice item is a pointer to get cursor field
• Wrote default test that uses order pointers orderPtrs against the default pagination test that tests the results against original orders.
• Feel free to try running the test case I added with current library code to see the Error reflect: call of reflect.Value.FieldByName on ptr Value.

[coveralls]

Pull Request Test Coverage Report for Build 43

• 5 of 5 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.04%) to 97.727%

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Totals
Change from base Build 41:	0.04%
Covered Lines:	172
Relevant Lines:	176

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💛 - Coveralls

[pilagod]

It works perfectly, nice : )