v1 of writeMastersOnly strategy for split_clone workers
Passing tests for v1 of writeMastersOnly strategy
Break out TestSplitClone into multiple tests
Modify sharding integration tests for vtworker to use writeMastersOnly strategy
Make vtworker find master tablets more efficiently when using writeMastersOnly strategy
Make writeMastersOnly into a proper parsed strategy
Merge pull request #153 from youtube/aaijazi_write_masters_only_strategy

writeMastersOnly strategy for split_clone workers