Bag of feedback for Node.JS wrapper

• (critical) operations on locked documents retry until timeout added test to show that unlock is not retried (see PR #127)
• (major) analytics metrics look copied from query metrics rather than being unique (I think they are)
• (major) key_value error_context does not include CAS
• (major) query metrics are optional, but are not represented like this in the query_meta_data
• (major) first_error_code, first_error_message are not included in error contexts
• (minor) Some "optionals" (like client_context_id) are not actual optionals, this breaks automated conversions since the default value is overwritten by 'undefined'.

Cleanup notes moved into CXXCBC-96

• (cleanup) there are areas in the API that we use std::string to represent JSON or Binary data, we should type these appropriately.
  • start_key,end_key, etc... for view queries
  • query_string option on view_query
• (cleanup) various type names are inconsistent across the APIs.
  • query_request::scan_consistency_type vs view_request::scan_consistency
  • some use the name scan_consistency, some use just consistency

critical - blocks tests from passing
major - minor issues, but can't be worked around in Node
minor - minor issues, can be worked around for now
cleanup - stuff we should fix before C++ GA, but not important to the Node.js release