MutationState not handled consistently

The mutation state should be treated consistently throughout the streaming APIs. Currently N1QL pass the mutation tokens to the bindings as as set and search passes mutation tokens to the bindings as a list. Lets treat mutation state as a set throughout all the SDK and pass it to the bindings as a list.

• Treat mutation state as a set of mutation tokens and passed to bindings as list.
• Add test to verify RYOW in query and search.
• Move mutation tokens utility methods from n1ql.cxx to utils.cxx (prep for future changes w/ kv rangescan).