Add a paginator to be used for all object types

[bnekolny]

Here is a sample paginator use-case: https://github.com/splunk/splunk-sdk-python/blob/70931cd7bc56a891f48c6f77469957b233aa0557/tests/test_collection.py#L213

[JasonSanford]

I got pagination working. It works like this: https://gist.github.com/JasonSanford/ddbe06832e5d17061b8a