* wait_for_index on write data due to use in upgrade tests
* clean-up other tests to that test upgrade from (2.0.5->2.0.6/2.1.1->2.1.2), namely yz_extractors
* clean-up tests that can start using yokozuna_rt helpers
* add count_calls and helpers for tracing fn calls (with dbg)
* add yz_extractors test to check for updates made in RIAK-1673
* add yz_noop_extractor intercept for testing a custom mimetype for extractor